- Synthesis and anti-acetylcholinesterase activities of novel glycosyl coumarylthiazole derivatives
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Eleven glycosyl coumarylthiazole derivatives are synthesized by cyclization and condensation of glycosyl thiourea with 3-bromoacetyl coumarins in ethanol. The reaction conditions are optimized and good yields of products (80%–95%) are obtained. The structures of all new products were confirmed by IR, 1H and 13C NMR, and by HRMS (electrospray ionization). The in vitro acetylcholinesterase (AChE) inhibitory activities of these new compounds are tested by Ellman’s method. Among them, N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranosyl)-4-(6-nitrocoumarinyl)-1,3-thiazole-2-amine showed the best activity with an in vitro AChE inhibitory rate of 58% and an IC50 value of 12 ± 0.38 μg/mL.
- Cao, Lian-Gong,Cao, Zhi-Ling,Jiang, Kai-Jun,Liu, Shu-Hao,Liu, Wei-Wei,Lu, Xing,Shao, Zhong-Bai,Shi, Da-Hua,Wang, Lei,Wang, You-Xian
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p. 359 - 364
(2020/12/28)
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- Synthesis and Anti-Cholinesterase Activity of Novel Glycosyl Benzofuranylthiazole Derivatives
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Abstract: A new series of glycosyl benzofuranylthiazole derivatives were designed, synthesized, characterized, and evaluated as potential candidates to treat Alzheimer’s disease. The compounds have been synthesized by the cyclocondensation of glycosyl thiourea with a variety of 2-(bromoacetyl)benzofurans. The reaction conditions have been optimized, and good yields (79–95%) have been obtained. The synthesized compounds showed different degrees of cholinesterase inhibitory activity.
- Cao, L.,Cao, Zh.,Chen, Ch.,Jiang, K.,Liu, Sh.,Liu, W.,Lu, X.,Shao, Zh.,Shi, D.,Su, Z.,Wang, L.,Wang, Y.,Wu, Y.
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p. 1513 - 1518
(2021/10/26)
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- Synthesis and anticholinesterase activities of novel glycosyl benzoxazole derivatives
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Eight glycosyl benzoxazole derivatives are synthesized by nucleophilic addition reactions of glycosyl isothiocyanate with o-aminophenol in tetrahydrofuran. The reaction conditions are optimized, and good yields (86%–94%) were obtained. The structures of all new products are confirmed by infrared, 1H nuclear magnetic resonance, and high-resolution mass spectrometry (electrospray ionization). In addition, the in vitro cholinesterase inhibitory activities of these new compounds are tested by Ellman’s method.
- Cao, Zhi-Ling,Liu, Shu-Hao,Liu, Wei-Wei,Ren, Shu-Ting,Shi, Da-Hua,Wang, Lei,Wang, You-Xian,Wu, Yu-Ran
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p. 363 - 366
(2020/02/05)
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- Glycosides and Glycoconjugates of the Diterpenoid Isosteviol with a 1,2,3-Triazolyl Moiety: Synthesis and Cytotoxicity Evaluation
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Several glycoconjugates of the diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) with a 1,2,3-triazolyl moiety were synthesized, and their cytotoxicity was evaluated against some human cancer and normal cell lines. Most of the synthesized compounds demonstrated weak inhibitory activities against the M-HeLa and MCF-7 human cancer cell lines. Three lead compounds, 54, 56 and 57, exhibited high selective cytotoxic activity against M-HeLa cells (IC50 = 1.7-1.9 μM) that corresponded to the activity of the anticancer drug doxorubicin (IC50 = 3.0 μM). Moreover, the lead compounds were not cytotoxic with respect to a Chang liver human normal cell line (IC50 > 100 μM), whereas doxorubicin was cytotoxic to this cell line (IC50 = 3.0 μM). It was found that cytotoxic activity of the lead compounds is due to induction of apoptosis proceeding along the mitochondrial pathway. The present findings suggest that 1,2,3-triazolyl-ring-containing glycoconjugates of isosteviol are a promising scaffold for the design of novel anticancer agents.
- Andreeva, Olga V.,Garifullin, Bulat F.,Sharipova, Radmila R.,Strobykina, Irina Yu.,Sapunova, Anastasiya S.,Voloshina, Alexandra D.,Belenok, Mayya G.,Dobrynin, Alexey B.,Khabibulina, Leysan R.,Kataev, Vladimir E.
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p. 2367 - 2380
(2020/08/28)
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- Biochemical Characterization and Structural Analysis of a β- N-Acetylglucosaminidase from Paenibacillus barengoltzii for Efficient Production of N-Acetyl- d -glucosamine
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Bioproduction of N-acetyl-d-glucosamine (GlcNAc) from chitin, the second most abundant natural renewable polymer on earth, is of great value in which chitinolytic enzymes play key roles. In this study, a novel glycoside hydrolase family-18 β-N-acetylglucosaminidase (PbNag39) from Paenibacillus barengoltzii suitable for GlcNAc production was identified and biochemically characterized. It possessed a unique shallow catalytic groove (5.8 ?) as well as a smaller C-terminal domain (solvent-accessible surface area, 5.1 × 103 ?2) and exhibited strict substrate specificity toward N-acetyl chitooligosaccharides (COS) with GlcNAc as the sole product, showing a typical manner of action of β-N-acetylglucosaminidases. Thus, an environmentally friendly bioprocess for GlcNAc production from ball-milled powdery chitin by an enzyme cocktail reaction was further developed. By using the new route, the powdery chitin conversion rate increased from 23.3% (v/v) to 75.3% with a final GlcNAc content of 22.6 mg mL-1. The efficient and environmentally friendly bioprocess may have great application potential in GlcNAc production.
- Liu, Yihao,Jiang, Zhengqiang,Ma, Junwen,Ma, Shuai,Yan, Qiaojuan,Yang, Shaoqing
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p. 5648 - 5657
(2020/06/03)
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- Simplified determination of the content and average degree of acetylation of chitin in crude black soldier fly larvae samples
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Insects are considered a promising alternative protein source for food and feed, but contain significant amounts of chitin, often undesirable due to indigestibility, disagreeable texture and negative effect on nutrients intake. Fractionation strategies are thus increasingly being applied to isolate and valorize chitin separately. The analysis of chitin generally requires an intensive pretreatment to remove impurities, and derivatization to generate sufficient detector response. In this work, a liquid chromatography method, without pretreatment nor derivatization, was developed for the simultaneous determination of chitin content and degree of acetylation in non-purified samples of black soldier fly (BSF) larvae. The method is found to be more suitable, compared to traditional methods, for assessing high degrees of acetylation. For the first time, the degree of acetylation of BSF chitin (81 ± 2%) is reported. Additionally, the chitin content of BSF soft tissues is estimated at approximately 20% of the total chitin content (8.5 ± 0.1%).
- D'Hondt, Els,Soetemans, Lise,Bastiaens, Leen,Maesen, Miranda,Jespers, Vincent,Van den Bosch, Bert,Voorspoels, Stefan,Elst, Kathy
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supporting information
(2020/01/25)
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- N-acetyltransferases from three different organisms displaying distinct selectivity toward hexosamines and N-terminal amine of peptides
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N-acetyltransferases are a family of enzymes that catalyze the transfer of the acetyl moiety (–COCH3) from acetyl coenzyme A (Acetyl-CoA) to a primary amine of acceptor substrates from small molecules such as aminoglycoside to macromolecules of various proteins. In this study, the substrate selectivity of three N-acetyltransferases falling into different phylogenetic groups was probed against a series of hexosamines and synthetic peptides. GlmA from Clostridium acetobutylicum and RmNag from Rhizomucor miehei, which have been defined as glucosamine N-acetyltransferases, were herein demonstrated to be also capable of acetylating the free amino group on the very first glycine residue of peptide in spite of varied catalytic efficiency. The human recombinant N-acetyltransferase of Naa10p, however, prefers primary amine groups in the peptides as opposed to glucosamine. The varied preference of GlmA, RmNag and Naa10p probably arose from the divergent evolution of these N-acetyltransferases. The expanded knowledge of acceptor specificity would as well facilitate the application of these N-acetyltransferases in the acetylation of hexosamines or peptides.
- Zhang, Peiru,Liu, Pei,Xu, Yangyang,Liang, Yulu,Wang, Peng George,Cheng, Jiansong
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- Aromatic butenolides produced by a soil ascomycete Auxarthron sp. KCB15F070 derived from a volcanic island
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LC/MS-based chemical screening of fungal extract fraction library led to identification of three 2,3-aryl substituted furanone metabolites (1–3), including one known butenolide glycoside (1) whose stereochemistry remained unsolved and two new compounds gotjawaside and gotjawalide (2 and 3), from Auxarthron sp. KCB15F070, a fungus isolated from a soil sample of the volcanic island Jeju, Korea. Their planar structures were elucidated by 1D- and 2D-NMR spectroscopic and HRESIMS spectrometric techniques, and the absolute configurations of three compounds were solved using a combination of chemical derivatizations and computational analysis of vibrational circular dichroism (VCD) spectra.
- Kim, Jong Won,Son, Sangkeun,Kim, Gil Soo,Otaka, Junnosuke,Miura, Yuzuki,Muranaka, Atsuya,Uchiyama, Masanobu,Lee, Jung-Sook,Jang, Mina,Ko, Sung-Kyun,Takahashi, Shunji,Osada, Hiroyuki,Jang, Jae-Hyuk,Ahn, Jong Seog
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- Structures of triterpenoids from the leaves of Lansium domesticum
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From the methanolic extract of the leaves of Lansium domesticum, three new onoceranoid-type triterpenoids, lansium acids X–XII and a new cycloartane-type triterpene, lansium acid XIII, were isolated. The chemical structures of the isolated new compounds were elucidated on the basis of chemical/physicochemical evidence. For new onoceranoid-type triterpenoids, the absolute configurations were established by comparison of experimental and predicted electronic circular dichroism (ECD) data. The isolated onoceranoid-type triterpenoids showed antimutagenic effects in the Ames assay against 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1).
- Matsumoto, Takahiro,Kitagawa, Takahiro,Ohta, Tomoe,Yoshida, Tatsusada,Imahori, Daisuke,Teo, Stephen,Ahmad, Haji Sapuan bin,Watanabe, Tetsushi
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p. 727 - 734
(2019/05/29)
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- Enzymatic synthesis of trideuterated sialosides
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Sialic acids are a family of acidic monosaccharides often found on the termini of cell surface proteins or lipid glycoconjugates of higher animals. Herein we describe the enzymatic synthesis of the two isotopically labeled sialic acid derivatives d3-X-Gal-a-2,3-Neu5Ac and d3-X-Gal-a-2,3-Neu5Gc. Using deuterium oxide as the reaction solvent, deuterium atoms could be successfully introduced during the enzymatic epimerization and aldol addition reactions when the sialosides were generated. NMR and mass spectrometric analyses confirmed that the resulting sialosides were indeed tri-deuterated. These compounds may be of interest as internal standards in liquid chromatography/mass spectrometric assays for biochemical or clinical studies of sialic acids. This was further exemplified by the use of this tri-deuterated sialosides as internal standards for the quantification of sialic acids in meat and egg samples.
- Cai, Zhi-P.,Conway, Louis P.,Huang, Ying Y.,Wang, Wen J.,Laborda, Pedro,Wang, Ting,Lu, Ai M.,Yao, Hong L.,Huang, Kun,Flitsch, Sabine L.,Liu, Li,Voglmeir, Josef
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- Structures and Antimutagenic Effects of Onoceranoid-Type Triterpenoids from the Leaves of Lansium domesticum
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A methanol extract of the dried leaves of Lansium domesticum showed antimutagenic effects against 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 2-amino-1-methyl-6-phenylimidazo[4,5-bI]pyridine (PhIP) using the Ames assay. Nine new onoceranoid-type triterpenoids, lansium acids I-IX (1-9), and nine known compounds (10-16) were isolated from the extract. The structures of the new compounds were elucidated on the basis of chemical and spectroscopic evidence. The absolute stereostructures of the new compounds were determined via their electronic circular dichroism spectra. Several isolated onoceranoid-type triterpeneoids showed antimutagenic effects in an in vitro Ames assay. Moreover, oral intake of a major constituent, lansionic acid (10), showed antimutagenic effects against PhIP in an in vivo micronucleus test.
- Matsumoto, Takahiro,Kitagawa, Takahiro,Teo, Stephen,Anai, Yuuka,Ikeda, Risa,Imahori, Daisuke,Ahmad, Haji Sapuan Bin,Watanabe, Tetsushi
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p. 2187 - 2194
(2018/10/25)
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- Bisabolane, cyclonerane, and harziane derivatives from the marine-alga-endophytic fungus Trichoderma asperellum cf44-2
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Three undescribed bisabolane derivatives, trichaspin, trichaspsides A and B, three undescribed cyclonerane sesquiterpenes, 9-cycloneren-3,7,11-triol, 11-cycloneren-3,7,10-triol, and 7,10-epoxycycloneran-3,11,12-triol, and one undescribed harziane diterpene, 11-hydroxy-9-harzien-3-one, were obtained from the culture of Trichoderma asperellum cf44-2, an endophyte of the marine brown alga Sargassum sp. Their structures and relative configurations were assigned by analysis of 1D/2D NMR and MS data, and their absolute configurations were established by ECD or specific optical rotation data. Trichaspin features an unprecedented ethylated bisabolane skeleton, while trichaspsides A and B represent the first aminoglycosides of bisabolane and norbisabolane sesquiterpenes, respectively. Nine of the compounds were evaluated for inhibition of five marine-derived pathogenic bacteria and toxicity to a marine zooplankton.
- Song, Yin-Ping,Liu, Xiang-Hong,Shi, Zhen-Zhen,Miao, Feng-Ping,Fang, Sheng-Tao,Ji, Nai-Yun
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- Albidosides H and I, two new triterpene saponins from the barks of Acacia albida Del. (Mimosaceae)
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Two new triterpene saponins, albidosides H (1) and I (2), along with the three known saponins were isolated from the barks of Acacia albida. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies and mass spectrometry. Albidosid
- Tchoukoua, Abdou,Kuiate Tabopda, Turibio,Konga Simo, Ingrid,Uesugi, Shota,Ohno, Misa,Kimura, Ken-ichi,Kwon, Eunsang,Momma, Hiroyuki,Shiono, Yoshihito,Ngadjui, Bonaventure Tchaleu
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p. 924 - 932
(2018/02/15)
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- Escherichia coli O106, a new member of a group of enteric bacteria sharing an O-polysaccharide backbone structure
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O-Polysaccharides (O-antigens) of a number of genetically related Escherichia coli O-serogroups (O17, O44, O73, O77, and O106) and Salmonella enterica O:6,14 possess an identical main chain composed of d-GlcNAc and d-Man residues and differ from each other by the absence or presence of glucose side chains at various positions. Using two-dimensional NMR spectroscopy, we established the structure of the O-polysaccharide of E. coli O106 having two glucose side chains in a hexasaccharide repeating unit.
- Shashkov,Senchenkova,Naumenko,Kalinchuk,Perepelov,Knirel, Yu. A.
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p. 1538 - 1541
(2018/10/31)
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- Process optimization, purification and characterization of a novel acidic, thermostable chitinase from Humicola grisea
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An extracellular acidic and thermostable chitinase (HgChi) from thermophilic Humicola grisea was purified and characterized. Enhancement in chitinase production (Qp = 2.9662 Ul?1 h?1) was achieved through derivation of optimum fermentation conditions via central composite design. H. grisea observed to produce various isoforms of chitinase, among which the major expressed form has molecular mass of about 50 kDa. Purified chitinases exhibited optimal activity at pH 3.0 and 70 °C. Chitinase showed notable stability at increasing temperatures. Half-life of chitinase is 169.06 min at optimum temperature. Chitinase has effectively catalyzed N-acetyl chitobiose (GlcNAc)2, and N-acetyl chitotriose (GlcNAc)3 and colloidal chitin. Purified chitinase from H. grisea showed high affinity towards colloidal chitin as evident by its comparatively lower Km value. Presence of metal ions viz. Mn2+, Co2+, NH4 + and Mg2+ significantly increased the chitinase activity. Thin layer chromatography (TLC) analysis revealed the significant hydrolyzing competence of HgChi for colloidal chitin, (GlcNAc)3 and (GlcNAc)2 into oligomers and N-acetyl–D-glucosamine (GlcNAc). Thermostable chitinase appeared as potential candidate for efficient conversion of chitin to bioactive oligosaccharides at industrial scale.
- Kumar, Manish,Brar, Amandeep,Vivekanand,Pareek, Nidhi
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p. 931 - 938
(2018/05/29)
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- Synthesis of Sialic Acids, Their Derivatives, and Analogs by Using a Whole-Cell Catalyst
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Sialic acids (Sias) are important constituents of cell surface glycans. Ready access to Sias in large quantities would facilitate the development of carbohydrate-based vaccines and small-molecule drugs. We now present a facile method for synthesizing various natural forms and non-natural derivatives or analogs of Sias by using a whole-cell catalyst, which is constructed by adding a plasmid containing necessary enzyme genes into a metabolically engineered strain of Escherichia coli. The flexible substrate tolerance of incorporated enzymes (N-acetylglucosamine 2-epimerase and N-acetylneuraminic acid aldolase) allows the cellular catalyst to convert a wide range of simple and inexpensive sugars into various Sia-related compounds through an easily scalable fermentation process. Further, syntheses using this whole-cell biotransformation in combination with three conventional enzymatic reactions provide a series of complex Sia-containing glycans (sialyloligosaccharides) and their derivatives bearing different substituents. The processes described herein should permit the large-scale and economical production of both Sias and sialyloligosaccharides, and may complement existing chemical and enzymatic strategies.
- Lv, Xun,Cao, Hongzhi,Lin, Baixue,Wang, Wei,Zhang, Wande,Duan, Qian,Tao, Yong,Liu, Xue-Wei,Li, Xuebing
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p. 15143 - 15149
(2017/10/17)
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- Carbohydrate Bis-acetal-Based Substrates as Tunable Fluorescence-Quenched Probes for Monitoring exo-Glycosidase Activity
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Tunable F?rster resonance energy transfer (FRET)-quenched substrates are useful for monitoring the activity of various enzymes within their relevant physiological environments. Development of FRET-quenched substrates for exo-glycosidases, however, has been hindered by their constrained pocket-shaped active sites. Here we report the design of a new class of substrate that overcomes this problem. These Bis-Acetal-Based Substrates (BABS) bear a hemiacetal aglycon leaving group that tethers fluorochromes in close proximity, also positioning them distant from the active site pocket. Following cleavage of the glycosidic bond, the liberated hemiacetal spontaneously breaks down, leading to separation of the fluorophore and quencher. We detail the synthesis and characterization of GlcNAc-BABS, revealing a striking 99.9% quenching efficiency. These substrates are efficiently turned over by the human exo-glycosidase O-GlcNAcase (OGA). We find the hemiacetal leaving group rapidly breaks down, enabling quantitative monitoring of OGA activity. We expect this strategy to be broadly useful for the development of substrate probes for monitoring exo-glycosidases, as well as a range of other enzymes having constrained pocket-shaped active sites.
- Cecioni, Samy,Vocadlo, David J.
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p. 8392 - 8395
(2017/07/06)
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- Pro-apoptotic activity of acylated triterpenoid saponins from the stem bark of Albizia chevalieri harms
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As a continuation of our interest in apoptosis-inducing triterpenoid saponins from Albizia genus, phytochemical investigation of the stem bark of Albizia chevalieri led to the isolation of three new oleanane-type saponins, named chevalierosides A–C (1–3). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H-, 13C NMR, DEPT, COSY, TOCSY, ROESY, HSQC and HMBC) experiments, HRESIMS studies, and by chemical evidence. The pro-apoptotic effect of the three saponins was evaluated on two human cell lines (pancreatic carcinoma AsPC-1 and hematopoietic monocytic THP-1). Cytometric analyses showed that saponins 1–3 induced apoptosis of both human cell lines (AsPC-1 and THP-1) in a dose-dependent manner.
- Noté, Olivier Placide,Messi, Lin Marcellin,Mbing, Joséphine Ngo,Azouaou, Sarah Ali,Sarr, Mamadou,Guillaume, Dominique,Muller, Christian Dominique,Pegnyemb, Dieudonné Emmanuel,Lobstein, Annelise
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- The α-Thioglycoligase Derived from a GH89 α-N-Acetylglucosaminidase Synthesises α-N-Acetylglucosamine-Based Glycosides of Biomedical Interest
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We report here on the preparation of a novel α-thioglycoligase that can be used for the fast and efficient synthesis of α-N-acetylglucosamine-based glycosides. Using the α-N-acetyl-glucosaminidase from Clostridium perfringens of family GH89 (according to the Carbohydrate Active Enzymes classification) as starting point, we prepared mutants in the acid/base residue glutamic acid 483 that were found to have different synthetic efficiencies (maximal yields >80% after 24 h) in the presence of an activated donor and suitable acceptors. The synthetic potential of the Glu483 alanine mutant as an α-thioglycoligase – only the third biocatalyst with this stereospecificity reported to date, and the first selective for the N-acetylglucosamine moiety – was demonstrated by producing for the first time N-acetyl-α-d-glucosaminyl azide and N-acetylglucosamine α-thioglycosides in high yields. To showcase the application of such compounds, we show that they offer the wild-type CpGH89 protection from thermal unfolding, demonstrating their potential as pharmacological chaperones for the treatment of mucopolysaccharidosis IIIB (Sanfilippo syndrome). (Figure presented.).
- Tshililo, Ndivhuwo Olga,Strazzulli, Andrea,Cobucci-Ponzano, Beatrice,Maurelli, Luisa,Iacono, Roberta,Bedini, Emiliano,Corsaro, Maria Michela,Strauss, Erick,Moracci, Marco
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supporting information
p. 663 - 676
(2017/02/23)
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- Isolation, structure elucidation and DFT study on two novel oligosaccharides from yak milk
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Two novel oligosaccharides were isolated from yak milk. The milk was processed by the method of Kobata and Ginsberg involving deproteination, centrifugation and lyophilization followed by gel filtrate chromatography acetylation and silica gel column chromatography of derivatized oligosaccharides while their homogeneity was confirmed by HPLC. The structures of these isolated oligosaccharides were elucidated by chemical transformation, chemical degradation, 1H, 13C NMR, 2D NMR (COSY, TOCSY and HSQC) and mass spectrometry. The geometry of compound A (Bosiose) and B (Bovisose) have been optimized at B3LYP method and 6-311 + G(d,p) basis set. The difference between the energies of A and B is 1.269 a.u. or 796.309 kcal/mol.
- Singh, Meenakshi,Kumar, Alok,Srivastava, Gaurav,Deepak, Desh,Singh
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- Sugar derived alkamine catalytic imine reduction method
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The invention discloses a method used for catalytic reduction of imine with saccharide-derivatized amino alcohol. According to the method, imine is taken as a substrate. The method comprises following steps: 1) imine and saccharide-derivatized amino alcohol are dissolved in an organic solvent I, wherein molar ratio of imine to saccharide-derivatized amino alcohol ranges from 100:1-20; 2) trichlorosilane with 1.5 to 5 times equivalent weights is added into a solution obtained via step 1) dropwise, an obtained mixture is stirred and reacted for 12 to 36h at a temperature of -20 to 40 DEG C, and a saturated sodium bicarbonate solution is used for quenching; 3) a material obtained via step 2) is extracted with an organic solvent II, and is subjected to column chromatography isolation so as to obtain amine compounds.
- -
-
Paragraph 0032; 0033; 0034
(2016/10/07)
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- Synthesis and biological evaluation of novel C1-glycosyl thiazole derivatives as acetylcholinesterase inhibitors
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A new series of C1-glycosyl thiazole derivatives was synthesised by the reaction of 1-(1,3,4,6-tetra-O-acetyl-2-deoxy-β-D-glucopyranos-2-yl)thiourea with 2-bromoacetophenone derivatives. Subsequent removal of the acetyl groups were conducted using NaOMe-MeOH. The structures of all new products were confirmed by IR, 1H NMR and HRMS (ESI). The acetylcholinesterase inhibitory activities of these new compounds were tested. Among them, N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranosyl)-4-(4-nitrophenyl)-1,3-thiazole-2-amine showed the best activity with an inhibition rate of 43.21%.
- Yin, Long,Cheng, Feng-Chang,Li, Qu-Xiang,Liu, Wei-Wei,Liu, Xiu-Jian,Cao, Zhi-Ling,Shi, Da-Hua
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p. 545 - 548
(2016/10/05)
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- Enzymatic glycosylation of indoxyglycosides catalyzed by a novel maltose phosphorylase from Emticicia oligotrophica
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Maltose phosphorylases (EC 2.4.1.8) catalyze the reversible conversion of maltose to glucose and glucose-1-phosphate in the presence of inorganic phosphate. Herein, we describe for the first time the use of a maltose phosphorylase for the synthesis of various anomerically modified diglycosides. The maltose phosphorylase used was isolated from the bacterium Emticicia oligotrophica and showed a high selectivity towards the phosphorolysis of maltose, whereas no phosphorolysis was observed using other glucose-containing disaccharides such as cellobiose, melibiose, sucrose and trehalose. The addition of glucose to various 5-bromo-4-chloro-3-indolyl-glycosides (X-sugars) was used to evaluate the promiscuity of the maltose phosphorylase, and product formation was verified by LC-ESI-MS and MALDI-TOF-MS. The simple expression and purification protocol and the use of maltose as an inexpensive starting material make this maltose phosphorylase from Emticicia oligotrophica a valuable novel biocatalyst for the synthesis of glucose-containing glycosides.
- Awad, Faisal Nureldin,Kulinich, Anna,Yao, Ming Jun,Duan, Xu Chu,Cai, Zhi Peng,Gu, Bin,Liu, Li,Voglmeir, Josef
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p. 301 - 314
(2016/12/07)
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- Kinetics and mechanism of degradation of chitosan by combining sonolysis with H2O2/ascorbic acid
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This study demonstrated the combined use of sonolysis with the H2O2/ascorbic acid (Vc) redox reaction to degrade chitosan (CS). The influence of operating parameters, such as the initial CS concentration (1-15 mg mL-1), the input power level (15-45% of the total input power), the H2O2 and Vc concentration (10-70 mM) and the pH (3.0-5.0) of the reaction solution, on the molecular weight and degradation kinetics of CS were investigated and optimized. Based on the degradation kinetics, a synergetic effect of sonolysis with H2O2 and Vc on the degradation of CS was observed. Structural analysis by FT-IR and 1H and 13C NMR indicated no significant difference between the chemical structure of chitosan before and after degradation. Moreover, intermolecular hydrogen bonds were broken, and the crystallinity of degraded chitosan decreased. Using the above analysis, CS degradation by the combination of sonolysis with the H2O2/Vc redox reaction was proposed to be due to mechanical effects along with HO attack on the β-1,4-glucoside linkages of glucosamine units. These results suggest that the sonolysis/H2O2/Vc combined technique is promisingly suitable for large-scale manufacture of chitooligosaccharide.
- Wu, Tiantian,Wu, Chunhua,Xiang, Yingchun,Huang, Jiaqi,Luan, Lanlan,Chen, Shiguo,Hu, Yaqin
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p. 76280 - 76287
(2016/08/30)
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- Chitooligosaccharide Synthesis Using an Ionic Tag
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An environmentally improved synthesis of the N-differentiated chitotetrasaccharide CO-IV-(NH2), a key intermediate for the preparation of lipochitooligosaccharides and the TMG-chitotriomycin, is reported based on a chromatography-free ionic-liquid tagging approach. The method involves the glycosylation of ionic-liquid-tagged acceptors with thioglucosamine donors leading to the stereoselective formation of β-(1→4)-linked glucosamine-containing oligomers.
- Gillard, Laura,Tran, Anh-Tuan,Boyer, Fran?ois-Didier,Beau, Jean-Marie
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supporting information
p. 1103 - 1109
(2016/03/05)
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- Cytotoxic Oleanane-Type Saponins from the Leaves of Albizia anthelmintica Brongn.
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Two new oleanane-type saponins: β-d-xylopyranosyl-(1 → 4)-6-deoxy-α-l-mannopyranosyl-(1 → 2)-1-O-{(3β)-28-oxo-3-[(2-O-β-d-xylopyranosyl-β-d-glucopyranosyl)oxy]olean-12-en-28-yl}-β-d-glucopyranose (1) and 1-O-[(3β)-28-oxo-3-{[β-d-xylopyranosyl-(1 → 2)-α-l-
- Al-Sayed, Eman,Eldahshan, Omayma A.,Bahgat, Dina M.,Singab, Abdel Nasser B.
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p. 1666 - 1673
(2016/12/14)
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- Unusual Cytotoxic Steroidal Saponins from the Gorgonian Astrogorgia dumbea
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Three steroidal saponins, including astrogorgiosides A (1) and B (2) bearing acetamido-glucose moieties, and astrogorgioside C (3) with a 19-nor and bearing an aromatized B ring steroid aglycone, together with a known major saponin dimorphoside A (4), were obtained from the gorgonian Astrogorgia dumbea collected near Dongshan Island in East China Sea. Structures of these compounds were elucidated by in-depth spectral and chemical methods, including 2D-NMR, HR-ESI-MS spectra, and acidic hydrolysis. For the first time, acetamido-glucose moiety is being reported from a gorgonian. The B-ring aromatized steroid aglycone of compound 3 is also rare in marine natural products. Compounds 1-3 exhibited moderate cytotoxic activity with IC50 values of 26.8-45.6 μM against human tumor cells Bel-7402 and K562.
- Lu, Ya-Nan,Cui, Ping,Tian, Xiao-Qing,Lou, Li-Guang,Fan, Cheng-Qi
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p. 882 - 887
(2016/07/11)
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- Catalytic Depolymerization of Chitin with Retention of N-Acetyl Group
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Chitin, a polymer of N-acetylglucosamine units with β-1,4-glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N-acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N-acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N-acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical-force-assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short-chain oligomers. Subsequent hydrolysis of the ball-milled sample provided N-acetylglucosamine in 53 % yield, and methanolysis afforded 1-O-methyl-N-acetylglucosamine in yields of up to 70 %. Our process can greatly reduce the use of acid compared to the conventional process.
- Yabushita, Mizuho,Kobayashi, Hirokazu,Kuroki, Kyoichi,Ito, Shogo,Fukuoka, Atsushi
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p. 3760 - 3763
(2015/12/08)
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- Synthesis of derivatized chitooligomers using transglycosidases engineered from the fungal GH20 β-N-acetylhexosaminidase
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Abstract The synthesis of oligosaccharides using mutant glycosidases has been dynamically developing due to the need for novel carbohydrate-based materials. Chitooligomers (β-1→4-linked oligomers of N-acetylglucosamine) are bioactive compounds applicable in many industrial and pharmacological areas; however, their accessibility is still rather low. In this work, GH20 β-N-acetylhexosaminidase from the fungus Talaromyces flavus was engineered by site-directed mutagenesis to obtain three efficiently transglycosylating variants with ca. 200-times suppressed hydrolytic activity. Thus, we have prepared the first GH20 transglycosidases. In the reactions catalyzed by these mutant β-N-acetylhexosaminidases we were able to easily prepare and isolate both natural and modified chitooligomers in sufficient amounts for their complete spectral characterization and possible further application. The presented method for the synthesis of chitooligomers with aglycones suitable for linking to other biological structures is simple and robust enough to be easily scaled up.
- Slámová, Kristyna,Krejzová, Jana,Marhol, Petr,Kalachova, Lubica,Kulik, Natallia,Pelantová, Helena,Cva?ka, Josef,K?en, Vladimír
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p. 1941 - 1950
(2015/06/02)
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- Diaminohexopyranosides as ligands in half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes
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The syntheses of methyl 2,3-diamino-4,6-O-benzylidene-2,3-dideoxy-α-d-hexopyranosides of glucose, mannose, gulose, and talose and methyl 2-amino-4,6-benzylidene-2,3-dideoxy-3-tosylamido-α-d-glucopyranoside are exhaustively presented, as well as their application as ligands in half-sandwich ruthenium(II), rhodium(III), and iridium(III) complexes. The complex formation occurs highly diastereoselectively, creating a stereogenic metal center. The molecular structures of the ligands and their complexes were investigated by X-ray structure analysis, NMR spectroscopy, polarimetry, and DFT methods. The diamino monosaccharide complexes have been subjected to antitumor activity studies. In vitro tests of a few ruthenium complexes against different cancer cell types showed antiproliferative activities 4-10 times lower than that of cisplatin.
- B?ge, Matthias,Fowelin, Christian,Bednarski, Patrick,Heck, Jürgen
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supporting information
p. 1507 - 1521
(2015/05/13)
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- Synthesis, characterization, and biological evaluation of some novel glycosyl 1,3,4-thiadiazole derivatives as acetylcholinesterase inhibitors
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The corresponding 4-substituted glycosyl thiosemicarbazide derivatives (6a-6l) were obtained by the reaction of glycosyl isothiocyanate 4 with various hydrazides. Further cyclization with the system of p-TsCl/TEA led to the formation of N-glycosyl-5-substituted 1,3,4-thiadiazole-2-amine (7a-7l). Subsequent removal of the acetyl groups were conducted using the system of NaOMe/MeOH. The chemical structures of all new products were confirmed by IR, 1H NMR and ESI-HRMS. The acetylcholinesterase (AChE) inhibitory activities of those compounds were tested by Ellman's method. Among them, the compound 8h possessed the best acetylcholinesterase-inhibition activity with IC50 of 18.38 ± 0.89 μM.
- Liu, Wei-Wei,Li, Qu-Xiang,Shi, Da-Hua,Cao, Zhi-Ling,Cheng, Feng-Chang,Tao, Chuan-Zhou,Yin, Long,Wang, Xuan
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p. 275 - 286
(2015/03/04)
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- Effect of Treatment Methods on Chitin Structure and Its Transformation into Nitrogen-Containing Chemicals
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Chitin treatment using different methods, including ball mill grinding, steam explosion, alkaline treatment, phosphoric acid, and ionic liquid (IL) dissolution/reprecipitation have been systematically investigated. The chitin structures were thoroughly investigated by using a series of analytical techniques, and the reactivity after each treatment was evaluated in dehydration and liquefaction reactions. The parallel studies enable direct comparisons of these methods and help to establish the structure-activity correlations. Ball mill grinding in dry mode was the most effective method, with the crystal size and the hydrogen-bond network being the two crucial factors in enhancing the reactivity. Remarkably, the yield of 3-acetamido-5-acetylfuran (3A5AF) from chitin dehydration increased to the highest amount (28.5%) after ball mill grinding (the previous record yield was 7.5% for untreated chitin).
- Chen, Xi,Gao, Yongjun,Wang, Lan,Chen, Hongzhang,Yan, Ning
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p. 1565 - 1572
(2015/10/19)
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- Structure and genetics of biosynthesis of the glycosyl phosphate-containing O-polysaccharide of Escherichia coli O160
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On mild acid degradation of the lipopolysaccharide of Escherichia coli O160, the O-polysaccharide was cleaved by acid-labile glycosyl phosphate linkages in the main chain. The resultant oligosaccharide and the alkali-treated lipopolysaccharide were studied by sugar analysis along with 1H and 13C NMR spectroscopies, and the following structure of the branched pentasaccharide repeating unit of the O-polysaccharide was established:β-D-G1cp The O-antigen gene cluster of E.coli O160 was found to be consistent with the O-polysaccharide structure established.
- Perepelov, Andrei V.,Guo, Xi,Senchenkova, Sof'ya N.,Shashkov, Alexander S.,Knirel, Yuriy A.
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- Synthesis of novel glycosyl 1,3,4-oxadiazole derivatives
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A convenient and practical protocol was developed to synthesize glycosyl 1,3,4-oxadiazoles from d-glucosamine with good to excellent yields. The key step involved p-TsCl/pyridine-mediated cyclization under mild conditions. Subsequent removal of the acetyl groups in the last step, conducted using the system of NaOMe/MeOH, gave the desired N-acetyl-d-glucosamine 1,3,4-oxadiazole derivatives.
- Liu, Weiwei,Li, Quxiang,Cheng, Fengchang,Shi, Dahua,Cao, Zhiling
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p. 333 - 338
(2015/02/05)
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- An ammonium sulfate sensitive chitinase from Streptomyces sp. CS501
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A chitinase from Streptomyces sp. CS501 was isolated from the Korean soil sample, purified by single-step chromatography, and biochemically characterized. The extracellular chitinase (Ch501) was purified to 4.60 fold with yield of 28.74 % using Sepharose Cl-6B column. The molecular mass of Ch501 was approximately 43 kDa as estimated by SDS-PAGE and zymography. The enzyme (Ch501) was found to be stable over a broad pH range (5.0-10.0) and temperature (up to 50 °C), and have an optimum temperature of 60 °C. N-terminal sequence of Ch501 was AAYDDAAAAA. Intriguingly, Ch501 was highly sensitive to ammonium sulfate but it's completely suppressed activity was recovered after desalting out. TLC analysis of Ch501 showed the production of N-acetyl d-glucosamine (GlcNAc) and Diacetylchitobiose (GlcNAc)2, as a principal hydrolyzed product. Ch501 shows antifungal activity against Fusarium solani and Aspergillus brasiliensis, which can be used for the biological control of fungus. As has been simple in purification, stable in a broad range of pH, ability to produce oligosaccharides, and antifungal activity showed that Ch501 has potential applications in industries as for chitooligosaccharides production used as prebiotics and/or for the biological control of plant pathogens in agriculture.
- Rahman, Md. Arifur,Choi, Yun Hee,Pradeep,Yoo, Jin Cheol
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p. 1522 - 1529
(2015/03/30)
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- Structure and gene cluster of the O-antigen of Escherichia coli O30
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The acidic O-polysaccharide (O-antigen) of Escherichia coli O30 was isolated from the lipopolysaccharide and studied by sugar analysis and NMR spectroscopy. The following structure of the branched tetrasaccharide repeating unit was established, which is u
- Perepelov, Andrei V.,Hao, Xiyan,Senchenkova, Sof'Ya N.,Shashkov, Alexander S.,Liu, Bin,Wang, Lei,Knirel, Yuriy A.
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p. 196 - 198
(2014/05/20)
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- Synthesis and characterization of N-acyl-tetra-O-acyl glucosamine derivatives
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Novel 1,3,4,6-tetra-O-acyl-N-acyl-d-glucosamine derivatives were synthesized from glucosamine hydrochloride (GlcN·HCl) by the acylation with pyridine as a catalyst. A derivative of tetra-O-acetyl glucosamine contained ketoprofen, a non-steroidal anti-inflammatory drug (NSAID) with analgesic and antipyretic effects, was first synthesized. In analysis of the NMR spectra, the ratio of α:β-anomer showed that penta-acyl-d- glucosamine derivatives and N-acetylated glucosamines containing O-acyl groups have been only the α-anomer. Meanwhile, both the intermediates and the glucoconjugate compound of ketoprofen have only the β-anomer.
- Dang, Chi-Hien,Nguyen, Cong-Hao,Nguyen, Thanh-Danh,Im, Chan
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p. 6239 - 6245
(2014/01/23)
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- Structure and activity of the streptomyces coelicolor A3(2) β-N-acetylhexosaminidase provides further insight into GH20 family catalysis and inhibition
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β-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-β-d-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic production of carbohydrates and glycomimetics. In this study, the three-dimensional structure of the wild-type and catalytically impaired E302Q HEX variant from the soil bacterium Streptomyces coelicolor A3(2) (ScHEX) were solved in ligand-free forms and in the presence of 6-acetamido-6-deoxy-castanospermine (6-Ac-Cas). The E302Q variant was also trapped as an intermediate with oxazoline bound to the active center. Crystallographic evidence highlights structural variations in the loop 3 environment, suggesting conformational heterogeneity for important active-site residues of this GH20 family member. The enzyme was investigated for its β-N-acetylhexosaminidase activity toward chitooligomers and pNP-acetyl gluco- and galacto-configured N-acetyl hexosaminides. Kinetic analyses confirm the β(1-4) glycosidic linkage substrate preference, and HPLC profiles support an exoglycosidase mechanism, where the enzyme cleaves sugars from the nonreducing end of substrates. ScHEX possesses significant activity toward chitooligosaccharides of varying degrees of polymerization, and the final hydrolytic reaction yielded pure GlcNAc without any byproduct, promising high applicability for the enzymatic production of this highly valued chemical. Thermostability and activation assays further suggest efficient conditions applicable to the enzymatic production of GlcNAc from chitooligomers.
- Thi, Nhung Nguyen,Offen, Wendy A.,Shareck, Francìois,Davies, Gideon J.,Doucet, Nicolas
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p. 1789 - 1800
(2014/04/17)
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- Comparative analysis of glycoside hydrolases activities from phylogenetically diverse marine bacteria of the genus Arenibacter
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A total of 16 marine strains belonging to the genus Arenibacter, recovered from diverse microbial communities associated with various marine habitats and collected from different locations, were evaluated in degradation of natural polysaccharides and chromogenic glycosides. Most strains were affiliated with five recognized species, and some presented three new species within the genus Arenibacter. No strains contained enzymes depolymerizing polysaccharides, but synthesized a wide spectrum of glycosidases. Highly active β-N- acetylglucosaminidases and α-N-acetylgalactosaminidases were the main glycosidases for all Arenibacter. The genes, encoding two new members of glycoside hydrolyses (GH) families, 20 and 109, were isolated and characterized from the genomes of Arenibacter latericius. Molecular genetic analysis using glycosidase-specific primers shows the absence of GH27 and GH36 genes. A sequence comparison with functionally-characterized GH20 and GH109 enzymes shows that both sequences are closest to the enzymes of chitinolytic bacteria Vibrio furnissii and Cellulomonas fimi of marine and terrestrial origin, as well as human pathogen Elisabethkingia meningoseptica and simbionts Akkermansia muciniphila, gut and non-gut Bacteroides, respectively. These results revealed that the genus Arenibacter is a highly taxonomic diverse group of microorganisms, which can participate in degradation of natural polymers in marine environments depending on their niche and habitat adaptations. They are new prospective candidates for biotechnological applications due to their production of unique glycosidases.
- Bakunina, Irina,Nedashkovskaya, Olga,Balabanova, Larissa,Zvyagintseva, Tatyana,Rasskasov, Valery,Mikhailov, Valery
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p. 1977 - 1998
(2013/07/26)
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- Structure and antioxidant activity study of sulfated acetamido- polysaccharide from Radix Hedysari
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A new sulfated acetamido-heteropolysaccharide, HPS4-2A, was obtained by aqueous extraction followed by precipitation with ethanol and fractionation with DEAE column chromatography from Radix Hedysari. It was composed of rhamnose, arabinose, glucose, galactose and 2-acetamido-2-deoxy-D-galactose in the molar ratio of 10.09%:25.90%:25.90%:25.0%:12.30%. Elemental analysis indicated that HPS4-2A was a sulfated polysaccharide containing small amount of sulfate groups (1.87%). Partial acid hydrolysis, GC, GC-MS, 1D and 2D NMR spectroscopy analysis of the HPS4-2A revealed a predominance of glucose, galactose and 2-acetamido-2-deoxy-D-galactose linked in a highly-branched structure. Themolecular weight of HPS4-2Awas determined by HPSEC and HPSEC-MALLS. AFMstudy indicated that HPS4-2A took a highly branched conformation, which in consistent with the result studied by SEC-MALLS. Structural features of HPS4-2A were also investigated by SEM and TEM. Antioxidant assays demonstrated that HPS4-2A possessed of strong DPPH and hydroxyl radicals scavenging activities, suggesting that HPS4-2A could potentially be used as natural antioxidant.
- Dang, Zilong,Feng, Demei,Liu, Xiaohua,Yang, Tao,Guo, Long,Liang, Jin,Liang, Jiandi,Hu, Fangdi,Cui, Fang,Feng, Shilan
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- Elimination of substrate inhibition of a β-N-acetyl-d-hexosaminidase by single site mutation
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Substrate inhibition hinders chitinolytic β-N-acetyl-d-hexosaminidases in producing N-acetyl-d-glucosamine (GlcNAc), the valuable chemical widely applied in medical and food industries. Here we focused on a promising chitinolytic enzyme, OfHex1 from the insect, Ostrinia furnacalis. By structural analysis of OfHex1, five residues nearby the active pocket including V327, E328, Y471, V484 and W490 were chosen and nine mutants including V327G, E328Q, E328A, Y471V, V484R, W490A, W490H, V327G/V484R/W490A and V327G/Y471V/W490H were constructed and recombinantly expressed in Pichia pastoris. The best-performing mutant, W490A, obtained by a higher yield of 5 mg/L, did not show substrate inhibition even when 5 mM of the substrates, (GlcNAc)2-4, were applied. The kcat/Km values for (GlcNAc)2-4 are 239.8, 111.3 and 79.8 s-1 mM-1, respectively. Besides, the pH stability of the mutant ranges from pH 4 to 11 and the thermal stability is up to 50 °C. This work suggests the W490A mutant might be an ideal biocatalyst for GlcNAc production from chitin.
- Liu, Tian,Wu, Qingyue,Liu, Lin,Yang, Qing
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p. 103 - 108
(2013/04/10)
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- Antitumor and immunomodulatory activities of a polysaccharide from Artemisia argyi
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A water-soluble polysaccharide (FAAP-02), composed of N-acetyl-d- glucosamine, glucose, mannose, galactose, rhamnose arabinose, xylose and ribose, with an average molecular weight of 5169 Da, was isolated from Artemisia argyi. The antitumor and immunomodulatory activities of FAAP-02 were evaluated in Sarcoma 180 (S180) tumor-bearing mice by intraperitoneal administration. As a result, FAAP-02 significantly inhibited the growth of the S180 transplanted tumors and prolonged the survival time of the tumor-bearing mice. Moreover, FAAP-02 could obviously increase the thymus and spleen indices, the levels of serum Interleukin 2 (IL-2), Interleukin 6 (IL-6), Interleukin 12 (IL-12) and tumor necrosis factor- α (TNF-α) and the expression of CD4+ and CD8+ splenic T lymphocytes which were suppressed by the transplanted tumor or/and 5-fluorouracil (5-FU) in the mice. These results indicated that the antitumor activity of FAAP-02 might be associated with its immunostimulatory effects.
- Bao, Xiaoli,Yuan, Huihui,Wang, Chengzhong,Liu, Jinjin,Lan, Minbo
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p. 1236 - 1243
(2013/10/22)
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- Inhibitors for bacterial cell-wall recycling
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Gram-negative bacteria have evolved an elaborate process for the recycling of their cell wall, which is initiated in the periplasmic space by the action of lytic transglycosylases. The product of this reaction, β-d-N- acetylglucosamine-(1a?'4)-1,6-anhydro-β-d-N-acetylmuramyl-l- Ala-I-d-Glu-meso-DAP-d-Ala-d-Ala (compound 1), is internalized to begin the recycling events within the cytoplasm. The first step in the cytoplasmic recycling is catalyzed by the NagZ glycosylase, which cleaves in a hydrolytic reaction the N-acetylglucosamine glycosidic bond of metabolite 1. The reactions catalyzed by both the lytic glycosylases and NagZ are believed to involve oxocarbenium transition species. We describe herein the synthesis and evaluation of four iminosaccharides as possible mimetics of the oxocarbenium species, and we disclose one as a potent (compound 3, Ki = 300 A± 15 nM) competitive inhibitor of NagZ.
- Yamaguchi, Takao,Blazquez, Blas,Hesek, Dusan,Lee, Mijoon,Llarrull, Leticia I.,Boggess, Bill,Oliver, Allen G.,Fisher, Jed F.,Mobashery, Shahriar
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supporting information; experimental part
p. 238 - 242
(2012/05/04)
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- Glycomimetic ligands for the human asialoglycoprotein receptor
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The asialoglycoprotein receptor (ASGPR) is a high-capacity galactose-binding receptor expressed on hepatocytes that binds its native substrates with low affinity. More potent ligands are of interest for hepatic delivery of therapeutic agents. We report several classes of galactosyl analogues with varied substitution at the anomeric, C2-, C5-, and C6-positions. Significant increases in binding affinity were noted for several trifluoromethylacetamide derivatives without covalent attachment to the protein. A variety of new ligands were obtained with affinity for ASGPR as good as or better than that of the parent N-acetylgalactosamine, showing that modification on either side of the key C3,C4-diol moiety is well tolerated, consistent with previous models of a shallow binding pocket. The galactosyl pyranose motif therefore offers many opportunities for the attachment of other functional units or payloads while retaining low-micromolar or better affinity for the ASGPR.
- Mamidyala, Sreeman K.,Dutta, Sanjay,Chrunyk, Boris A.,Preville, Cathy,Wang, Hong,Withka, Jane M.,McColl, Alexander,Subashi, Timothy A.,Hawrylik, Steven J.,Griffor, Matthew C.,Kim, Sung,Pfefferkorn, Jeffrey A.,Price, David A.,Menhaji-Klotz, Elnaz,Mascitti, Vincent,Finn
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supporting information; experimental part
p. 1978 - 1981
(2012/03/11)
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- Conversion of cysteine into dehydroalanine enables access to synthetic histones bearing diverse post-translational modifications
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Six for the price of one: From a single precursor, dehydroalanine, six distinct post-translational modifications can be site-selectively installed on histone proteins (see figure), including the first site-selective phosphorylation and glycosylation of histones. Direct observation of histone deacetylase activity on a full-length modified histone as well as its interactions with both chromatin reader and writer/eraser proteins are reported.
- Chalker, Justin M.,Lercher, Lukas,Rose, Nathan R.,Schofield, Christopher J.,Davis, Benjamin G.
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supporting information; experimental part
p. 1835 - 1839
(2012/04/04)
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- METHOD FOR PRODUCING N-ACETYL-D-GLUCOSAMINE
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The present invention relates to a novel process for producing N-acetyl-D-Glucosamine from Glucosamine hydrochloride. More particularly this invention pertains to a novel and simple environmentally acceptable process for producing glucosamine base solution in water, with very low halide content. Glucosamine base in solution with >95% chloride ion removal is further reacted with acylating agent to produce N-acetyl-D-Glucosamine with >99% purity and chloride content of 0.1%.
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Page/Page column 3
(2012/10/23)
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- Effect of sub- and supercritical water pretreatment on enzymatic degradation of chitin
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We examined the effect of sub- and supercritical water pretreatment (300-400 °C, 0.5-15 min) on enzymatic degradation of chitin to N,N′-diacetylchitobiose (GlcNAc)2. The yield of (GlcNAc) 2 by enzymatic degradation of supercritical water pretreated chitin at 400 °C for 1.0 min was up to 37%, compared to 5% without the pretreatment. X-ray diffraction (XRD) analysis revealed that the d-spacing and the crystallite size increased by sub- and supercritical water pretreatment, which is indicative of swelling of the chitin. The swelling of the chitin crystal structure improved enzymatic degradation by allowing the enzymes easy access to the chitin.
- Osada, Mitsumasa,Miura, Chika,Nakagawa, Yuko S.,Kaihara, Mikio,Nikaido, Mitsuru,Totani, Kazuhide
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body text
p. 308 - 312
(2012/05/19)
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- Structure elucidation of the O-antigen of Salmonella enterica O51 and its structural and genetic relation to the O-antigen of Escherichia coli O23
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The O-polysaccharide (O-antigen) of Salmonella enterica O51 was isolated by mild acid degradation of the lipopolysaccharide and its structure was established using sugar analysis and NMR spectroscopy. The O-antigen of Escherichia coli O23, whose structure was elucidated earlier, possesses a similar structure and differs only in the presence of an additional lateral α-D-Glcp residue at position 6 of the GlcNAc residue in the main chain. Sequencing of the O-antigen gene clusters of S. enterica O51 and E. coli O23 revealed the same genes with a high-level similarity. By comparison with opened gene databases, all genes expected for the synthesis of the common structure of the two O-antigens were assigned functions. It is suggested that the gene clusters of both bacteria originated from a common ancestor, whereas the O-antigen modification in E. coli O23, which, most probably, is induced by prophage genes outside the gene cluster, could be introduced after the species divergence.
- Perepelov,Liu, Bin,Guo, Dan,Senchenkova,Shahskov,Feng, Lu,Wang, Lei,Knirel
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experimental part
p. 774 - 779
(2012/01/19)
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- Enzymatic characterization and molecular modeling of an evolutionarily interesting fungal β-N-acetylhexosaminidase
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Fungal β-N-acetylhexosaminidases are inducible extracellular enzymes with many biotechnological applications. The enzyme from Penicillium oxalicum has unique enzymatic properties despite its close evolutionary relationship with other fungal hexosaminidases. It has high GalNAcase activity, tolerates substrates with the modified N-acyl group better and has some other unusual catalytic properties. In order to understand these features, we performed isolation, biochemical and enzymological characterization, molecular cloning and molecular modelling. The native enzyme is composed of two catalytic units (65 kDa each) and two propeptides (15 kDa each), yielding a molecular weight of 160 kDa. Enzyme deglycosylated by endoglycosidase H had comparable activity, but reduced stability. We have cloned and sequenced the gene coding for the entire hexosaminidase from P. oxalicum. Sufficient sequence identity of this hexosaminidase with the structurally solved enzymes from bacteria and humans with complete conservation of all catalytic residues allowed us to construct a molecular model of the enzyme. Results from molecular dynamics simulations and substrate docking supported the experimental kinetic and substrate specificity data and provided a molecular explanation for why the hexosaminidase from P. oxalicum is unique among the family of fungal hexosaminidases. Enzymes hexosaminidase, β-N-acetyl-d-hexosaminide N-acetylhexosaminhydrolase, Fungal β-N-acetylhexosaminidases are inducible extracellular enzymes with many biotechnological applications. The enzyme from Penicillium oxalicum has unique enzymatic properties despite its close evolutionary relationship with other fungal hexosaminidases. Results from molecular dynamics simulations and substrate docking supported the experimental kinetic and substrate specificity data, and identified a secondary binding site for the substrate close to the catalytic site. 2011 The Authors Journal compilation
- Ryslava, Helena,Kalendova, Alzbeta,Doubnerova, Veronika,Skocdopol, Premysl,Kumar, Vinay,Kukacka, Zdenek,Pompach, Petr,Vanek, Ondrej,Slamova, Kristyna,Bojarova, Pavla,Kulik, Natallia,Ettrich, Rudiger,Kren, Vladimir,Bezouska, Karel
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experimental part
p. 2469 - 2484
(2012/06/04)
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