- A (13)C-N.M.R. INVESTIGATION OF GLYCOSYL AZIDES AND OTHER AZIDO SUGARS: STEREOCHEMICAL INFLUENCES ON THE ONE-BOND (13)C-(1)H COUPLING CONSTANTS
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Unambigous (13)C assignments have been obtained, using 2D-n.m.r. techniques, for several glycosyl azides, 6-deoxyglucosyl azides, 2-acylamino-2-deoxyglycosyl azide, and some 2- and 3-azido monosaccharide derivatives.For non-anomeric C-H-bonds the 1JC,Heq. values are 4-9 Hz larger than the 1JC,Hαx. values.A substituent (hydroxyl, acetoxyl, alkoxyl, azido, etc.) in 1,3-diaxial relationship with Hax. significantly increases the value of 1JC,Hαx..Bond-angle distortions in the fused-ring bicyclic systems of some isopropylidene derivatives result in 1JC,Hαx. values being larger than 1JC,Heq. values.Electronic and stericeffects of substituents at non-anomeric carbons may alter the 1JC,H values for anomeric carbons to such an extent that they may no longer be useful for diagnosing anomeric configuration.Bond-angle deformations also influence the (13)C chemical shift differences in α- and β-anomers at C-5 and, to a lesser extent, at C-3.
- Szilagyi, Laszlo,Gyoergydeak, Zoltan
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- Site-specific glycoconjugation of protein via bioorthogonal tetrazine cycloaddition with a genetically encoded trans -cyclooctene or bicyclononyne
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Efficient access to proteins modified site-specifically with glycans is important in glycobiology and for therapeutic applications. Herein, we report a biocompatible protein glycoconjugation by inverse demand Diels-Alder reaction between tetrazine and tra
- Machida, Takuya,Lang, Kathrin,Xue, Lin,Chin, Jason W.,Winssinger, Nicolas
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Read Online
- Rapid glycoconjugation with glycosyl amines
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Conjugation of unprotected carbohydrates to surfaces or probes by chemoselective ligation reactions is indispensable for the elucidation of their numerous biological functions. In particular, the reaction with oxyamines leading to the formation of carbohydrate oximes which are in equilibrium with cyclic N-glycosides (oxyamine ligation) has an enormous impact in the field. Although highly chemoselective, the reaction is rather slow. Here, we report that the oxyamine ligation is significantly accelerated without the need for a catalyst when starting with glycosyl amines. Reaction rates are increased up to 500-fold compared to the reaction of the reducing carbohydrate. For comparison, aniline-catalyzed oxyamine ligation is only increased 3.8-fold under the same conditions. Glycosyl amines from mono- and oligosaccharides are easily accessible from reducing carbohydrates via the corresponding azides by using Shoda's reagent (2-chloro-1,3-dimethylimidazolinium chloride, DMC) and subsequent reduction. Furthermore, glycosyl amines are readily obtained by enzymatic release from N-glycoproteins making the method suited for glycomic analysis of these glycoconjugates which we demonstrate employing RNase B. Oxyamine ligation of glycosyl amines can be carried out at close to neutral conditions which makes the procedure especially valuable for acid-sensitive oligosaccharides. This journal is
- Baudendistel, Oliver R.,Rapp, Mareike A.,Steiner, Ulrich E.,Wittmann, Valentin
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p. 14901 - 14906
(2021/12/02)
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- Radical-Mediated Acyl Thiol-Ene Reaction for Rapid Synthesis of Biomolecular Thioester Derivatives
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The thiol-ene ‘click’ reaction has emerged as a versatile process for carbon–sulfur bond formation with widespread applications in chemical biology, medicinal chemistry and materials science. Thioesters are key intermediates in a wide range of synthetic and biological processes and efficient methods for their synthesis are of considerable interest. Herein, we report the first examples of acyl-thiol-ene (ATE) for the synthesis of biomolecular thioesters, including peptide, lipid and carbohydrate derivatives. A key finding is the profound effect of the amino acid side chain on the outcome of the ATE reaction. Furthermore, radical generated thioesters underwent efficient S-to-N acyl transfer and desulfurisation to furnish ‘sulfur-free’ ligation products in an overall amidation process with diverse applications for chemical ligation and bioconjugation.
- Lynch, Dylan M.,McLean, Joshua T.,McSweeney, Lauren,Milbeo, Pierre,Scanlan, Eoin M.
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supporting information
p. 4148 - 4160
(2021/08/24)
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- Synthesis of Asparagine Derivatives Harboring a Lewis X Type DC-SIGN Ligand and Evaluation of their Impact on Immunomodulation in Multiple Sclerosis
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The protein myelin oligodendrocyte glycoprotein (MOG) is a key component of myelin and an autoantigen in the disease multiple sclerosis (MS). Post-translational N-glycosylation of Asn31 of MOG seems to play a key role in modulating the immune response towards myelin. This is mediated by the interaction of Lewis-type glycan structures in the N-glycan of MOG with the DC-SIGN receptor on dendritic cells (DCs). Here, we report the synthesis of an unnatural Lewis X (LeX)-containing Fmoc-SPPS-compatible asparagine building block (SPPS=solid-phase peptide synthesis), as well as asparagine building blocks containing two LeX-derived oligosaccharides: LacNAc and Fucα1-3GlcNAc. These building blocks were used for the glycosylation of the immunodominant portion of MOG (MOG31-55) and analyzed with respect to their ability to bind to DC-SIGN in different biological setups, as well as their ability to inhibit the citrullination-induced aggregation of MOG31-55. Finally, a cytokine secretion assay was carried out on human monocyte-derived DCs, which showed the ability of the neoglycopeptide decorated with a single LeX to alter the balance of pro- and anti-inflammatory cytokines, inducing a tolerogenic response.
- Doelman, Ward,Marqvorsen, Mikkel H. S.,Chiodo, Fabrizio,Bruijns, Sven C. M.,van der Marel, Gijsbert A.,van Kooyk, Yvette,van Kasteren, Sander I.,Araman, Can
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supporting information
p. 2742 - 2752
(2020/12/29)
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- Glycoconjugated Metallohelices have Improved Nuclear Delivery and Suppress Tumour Growth In Vivo
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Monosaccharides are added to the hydrophilic face of a self-assembled asymmetric FeII metallohelix, using CuAAC chemistry. The sixteen resulting architectures are water-stable and optically pure, and exhibit improved antiproliferative selectivity against colon cancer cells (HCT116 p53+/+) with respect to the non-cancerous ARPE-19 cell line. While the most selective compound is a glucose-appended enantiomer, its cellular entry is not mainly glucose transporter-mediated. Glucose conjugation nevertheless increases nuclear delivery ca 2.5-fold, and a non-destructive interaction with DNA is indicated. Addition of the glucose units affects the binding orientation of the metallohelix to naked DNA, but does not substantially alter the overall affinity. In a mouse model, the glucose conjugated compound was far better tolerated, and tumour growth delays for the parent compound (2.6 d) were improved to 4.3 d; performance as good as cisplatin but with the advantage of no weight loss in the subjects.
- Allison, Simon J.,Brabec, Viktor,Bridgewater, Hannah E.,Kasparkova, Jana,Kostrhunova, Hana,Novohradsky, Vojtech,Phillips, Roger M.,Pracharova, Jitka,Rogers, Nicola J.,Scott, Peter,Shepherd, Samantha L.,Song, Hualong
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supporting information
p. 14677 - 14685
(2020/07/13)
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- A Tripeptide Approach to the Solid-Phase Synthesis of Peptide Thioacids and N-Glycopeptides
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A general and robust method for the incorporation of aspartates with a thioacid side chain into peptides has been developed. Pseudoproline tripeptides served as building blocks for the efficient fluorenylmethyloxycarbonyl (Fmoc) solid-phase synthesis of t
- Sch?we, Markus Julian,Keiper, Odin,Unverzagt, Carlo,Wittmann, Valentin
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supporting information
p. 15759 - 15764
(2019/11/19)
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- Core fucosylation of maternal milk N-glycan evokes B cell activation by selectively promoting the L-fucose metabolism of gut bifidobacterium spp. and lactobacillus spp
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The maternal milk glycobiome is crucial for shaping the gut microbiota of infants. Although high core fucosylation catalyzed by fucosyltransferase 8 (Fut8) is a general feature of human milk glycoproteins, its role in the formation of a healthy microbiota has not been evaluated. In this study, we found that the core-fucosylated N-glycans in milk of Chinese mothers selectively promoted the colonization of specific gut microbial groups, such as Bifidobacterium spp. and Lactobacillus spp. in their breast-fed infants during lactation. Compared with Fut8+/+ (WT) mouse-fed neonates, the offspring fed by Fut8+/-maternal mice had a distinct gut microbial profile, which was featured by a significant reduction of Lactobacillus spp., Bacteroides spp., and Bifidobacterium spp. and increased abundance of members of the Lachnospiraceae NK4A136 group and Akkermansia spp. Moreover, these offspring mice showed a lower proportion of splenic CD19+ CD69+ B lymphocytes and attenuated humoral immune responses upon ovalbumin (OVA) immunization. In vitro studies demonstrated that the chemically synthesized core-fucosylated oligosaccharides possessed the ability to promote the growth of tested Bifidobacterium and Lactobacillus strains in minimal medium. The resulting L-fucose metabolites, lactate and 1,2-propanediol, could promote the activation of B cells via the B cell receptor (BCR)-mediated signaling pathway. IMPORTANCE This study provides novel evidence for the critical role of maternal milk protein glycosylation in shaping early-life gut microbiota and promoting B cell activation of neonates. The special core-fucosylated oligosaccharides might be promising prebiotics for the personalized nutrition of infants.
- Li, Ming,Bai, Yaqiang,Zhou, Jiaorui,Huang, Wei,Yan, Jingyu,Tao, Jia,Fan, Qingjie,Liu, Yang,Mei, Di,Yan, Qiulong,Yuan, Jieli,Malard, Patrice,Wang, Zhongfu,Gu, Jianguo,Tanigchi, Naoyuki,Li, Wenzhe
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- Combining Click Reactions for the One-Pot Synthesis of Modular Biomolecule Mimetics
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Here, we report on the first combined one-pot use of the two so-called "click reactions": The thiol-ene coupling and the copper-catalyzed alkyne-azide cycloaddition. These reactions were employed in an alternating and one-pot fashion to combine appropriately functionalized monomeric carbohydrate building blocks to create mimics of trisaccharides and tetrasaccharides as single anomers, with only minimal purification necessary. The deprotected oligosaccharide mimics were found to bind both plant lectins and human galectin-3.
- Brink?, Anne,Risinger, Christian,Lambert, Annie,Blixt, Ola,Grandjean, Cyrille,Jensen, Henrik H.
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supporting information
p. 7544 - 7548
(2019/10/08)
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- Synthesis and self-assembling properties of 4,6?O-benzylidene acetal protected D-glucose and D-glucosamine β?1,2,3?triazole derivatives
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Sugar based low molecular weight gelators (LMWGs) are useful small molecules that can form reversible supramolecular gels with many applications. Selective functionalization of common monosaccharides has resulted in several classes of effective LMWGs. Rec
- Chen, Anji,Okafor, Ifeanyi S.,Garcia, Consuelo,Wang, Guijun
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- Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles
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Glycoscience, despite its myriad of challenges, promises to unravel the causes of, potential new detection methods for, and novel therapeutic strategies against, many disease states. In the last two decades, glyco-gold nanoparticles have emerged as one of several potential new tools for glycoscientists. Glyco-gold nanoparticles consist of the unique structural combination of a gold nanoparticle core and an outer-shell comprising multivalent presentation of carbohydrates. The combination of the distinctive physicochemical properties of the gold core and the biological function/activity of the carbohydrates makes glyco-gold nanoparticles a valuable tool in glycoscience. In this review we present recent advances made in the use of one type of click chemistry, namely the azide-alkyne Huisgen cycloaddition, for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles.
- Poonthiyil, Vivek,Lindhorst, Thisbe K.,Golovko, Vladimir B.,Fairbanks, Antony J.
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supporting information
p. 11 - 24
(2018/02/06)
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- Complete tetraglycosylation of a calix[4]arene by a chemo-enzymatic approach
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Polyglycosylated calixarenes are efficient and selective multivalent ligands for lectins. However, the chemical decoration of these macrocyclic scaffolds with saccharides of increasing complexity is hampered by the highly complex chemistry of carbohydrates. An alternative to the conventional approach is the enzymatic diversification of simple glycocluster-presented glycans. In this work, we present a highly efficient chemo-enzymatic approach to tetra-N-acetyl-lactosaminylcalix[4]arene via glycan extension catalyzed by a human β-1,4-galactosyltransferase. This demonstrates that calixarenes can be exhaustively processed by enzymatic glycosyl transfer despite the heavy steric crowding, paving the way to the design and achievement of multivalent ligands based on these macrocyclic scaffolds having complex branched glycans.
- Bernardi, Silvia,Yi, Dong,He, Ning,Casnati, Alessandro,Fessner, Wolf-Dieter,Sansone, Francesco
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p. 10064 - 10072
(2017/12/26)
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- Nickel-Catalyzed Azide-Alkyne Cycloaddition to Access 1,5-Disubstituted 1,2,3-Triazoles in Air and Water
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Transition-metal-catalyzed or metal-free azide-alkyne cycloadditions are methods to access 1,4- or 1,5-disubstituted 1,2,3-triazoles. Although the copper-catalyzed cycloaddition to access 1,4-disubstituted products has been applied to biomolecular reaction systems, the azide-alkyne cycloaddition to access the complementary 1,5-regioisomers under aqueous and ambient conditions remains a challenge due to limited substrate scope or moisture-/air-sensitive catalysts. Herein, we report a method to access 1,5-disubstituted 1,2,3-triazoles using a Cp2Ni/Xantphos catalytic system. The reaction proceeds both in water and organic solvents at room temperature. This protocol is simple and scalable with a broad substrate scope including both aliphatic and aromatic substrates. Moreover, triazoles attached with carbohydrates or amino acids are prepared via this cycloaddition.
- Kim, Woo Gyum,Kang, Mi Eun,Lee, Jae Bin,Jeon, Min Ho,Lee, Sungmin,Lee, Jungha,Choi, Bongseo,Cal, Pedro M. S. D.,Kang, Sebyung,Kee, Jung-Min,Bernardes, Gon?alo J. L.,Rohde, Jan-Uwe,Choe, Wonyoung,Hong, Sung You
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supporting information
p. 12121 - 12124
(2017/09/12)
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- Tetranuclear zinc cluster: A dual purpose catalyst for per-: O -acetylation and de- O -acetylation of carbohydrates
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The trifluoroacetic acid adduct of tetranuclear zinc cluster Zn4(OCOCF3)6O catalysis in per-O-acetylation and de-O-acetylation of carbohydrates at 70 °C can be tuned by adjusting the reaction medium. Per-O-acetylation of hexopyranoses with a near stoichiometric amount of acetic anhydride in toluene resulted in the exclusive formation of pyranosyl products as an anomeric mixture, whereas de-O-acetylation of acetates occurred in methanol in high yields. In the latter, methanol acts as both nucleophile and solvent, and the reaction conditions were compatible to acid- and base-sensitive groups and amino acid derivatives.
- Lin, Ting-Wei,Adak, Avijit K.,Lin, Hong-Jyune,Das, Anindya,Hsiao, Wei-Chen,Kuan, Ting-Chun,Lin, Chun-Cheng
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p. 58749 - 58754
(2016/07/07)
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- Site-Selective Chemoenzymatic Glycosylation of an HIV-1 Polypeptide Antigen with Two Distinct N-Glycans via an Orthogonal Protecting Group Strategy
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A convergent chemoenzymatic approach for sequential installation of different N-glycans in a polypeptide is described. The method includes introduction of distinguishably protected GlcNAc-Asn building blocks during automated solid phase peptide synthesis (SPPS), followed by orthogonal deprotection of the GlcNAc primers and site-selective sequential extension of the sugar chains through glycosynthase-catalyzed transglycosylation reactions. It was observed that the protecting groups on one neighboring GlcNAc moiety have an impact on the substrate activity of another GlcNAc acceptor toward some endoglycosynthases in transglycosylation. The usefulness of this synthetic strategy was exemplified by an efficient synthesis of the glycopeptide neutralizing epitope of broadly HIV-neutralizing antibody PG9. The method should be generally applicable for the synthesis of complex glycopeptides carrying multiple different N-glycans.
- Toonstra, Christian,Amin, Mohammed N.,Wang, Lai-Xi
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p. 6176 - 6185
(2016/08/16)
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- Endo-β-N-Acetylglucosaminidase catalysed glycosylation: Tolerance of enzymes to structural variation of the glycosyl amino acid acceptor
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Endo-β-N-Acetylglucosaminidases (ENGases) are highly useful biocatalysts that can be used to synthetically access a wide variety of defined homogenous N-linked glycoconjugates in a convergent manner. The synthetic efficiency of a selection of family GH85
- Tomabechi, Yusuke,Squire, Marie A.,Fairbanks, Antony J.
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p. 942 - 955
(2014/02/14)
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- Protecting-group-free one-pot synthesis of glycoconjugates directly from reducing sugars
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The conversion of sugars into glycomimetics typically involves multiple protecting-group manipulations. The development of methodology allowing the direct aqueous conversion of free sugars into glycosides, and mimics of oligosaccharides and glycoconjugates in a high-yielding and stereoselective process is highly desirable. The combined use of 2-azido-1,3-dimethylimidazolinium hexafluorophosphate and the Cu-catalyzed Huisgen cycloaddition allowed the synthesis of a range of glycoconjugates in a one-step reaction directly from reducing sugars under aqueous conditions. The reaction, which is completely stereoselective, may be applied to the convergent synthesis of triazole-linked glycosides, oligosaccharides, and glycopeptides. The procedure provides a method for the one-pot aqueous ligation of oligosaccharides and peptides bearing alkyne side chains.
- Lim, David,Brimble, Margaret A.,Kowalczyk, Renata,Watson, Andrew J.A.,Fairbanks, Antony John
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supporting information
p. 11907 - 11911
(2015/02/19)
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- Rapid formation of N-glycopeptides via Cu(II)-promoted glycosylative ligation
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Herein is described the chemoselective Cu(II)-HOBt promoted chemical ligation of glycosylamines and peptide thioacids to give N-glycosylated peptides. The method is distinguished from other chemical approaches to peptide N-glycosylation in that (1) it can be employed in the presence of unprotected N-terminal and Lys side chain amines; (2) it is remarkably fast, going to completion in under 30 min; and (3) it produces glycopeptides without attendant aspartimide formation.
- Joseph, Ryan,Dyer, Frank Brock,Garner, Philip
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supporting information
p. 732 - 735
(2013/03/29)
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- Regiospecific anomerisation of acylated glycosyl azides and benzoylated disaccharides by using TiCl4
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Chelation induced anomerisation is promoted when Lewis acids, such as TiCl4 or SnCl4, coordinate to the pyranose ring oxygen atom and another site, giving rise to endocyclic cleavage and isomerisation to the more stable anomer. In this research regiospecific site-directed anomerisation is demonstrated. TiCl4 (2.5equiv) was employed to induce anomerisation of 15 glycosyl azide and disaccharide substrates of low reactivity, and high yields (>75 %) and stereoselectivies (α/β>9:1) were achieved. The examples included glucopyranuronate, galactopyranuronate and mannopyranuronate as well as N-acetylated glucopyranuronate and galactopyranuronate derivatives. A disaccharide with the α1→4 linkage found in polygalacturonan was included. The use of benzoylated saccharides was found to be important in disaccharide anomerisation as attempts to isomerise related acetyl protected and 2,3-carbonate protected derivatives were not successful. Copyright
- Farrell, Mark,Zhou, Jian,Murphy, Paul V.
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p. 14836 - 14851
(2013/11/06)
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- SnCl4/Sn catalyzed chemoselective reduction of glycopyranosyl azides for the synthesis of diversely functionalized glycopyranosyl chloroacetamides
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A method for the chemoselective reduction of glycopyranosyl azides using SnCl4 and tin metal as the reducing agent followed by in situ chloroacetylation of the synthesized glycopyranosyl amine was developed. This reaction is applicable to diversely functionalized glycopyranosyl azides for the synthesis of glycopyranosyl chloroacetamides.
- Sahoo, Laxminarayan,Singhamahapatra, Anadi,Paul, Katuri J.V.,Loganathan, Duraikkannu
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p. 5361 - 5365
(2013/09/12)
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- Chemo-enzymatic synthesis of functionalized oligomers of N-acetyllactosamine glycan derivatives and their immobilization on biomaterial surfaces
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Poly-N-acetyllactosamines (poly-LacNAc, [-3Gal(β1-4)GlcNAc(β1-] n) are terminal glycan structures present in glycoproteins and glycolipids. Their biological functions as ligands for galectins and as carriers of glycan epitopes are well documented. In the present paper we have characterized six novel functionalized β-d-GlcNAc derivatives, including aglyca of varying hydrophobicity and molecular weight, as substrates for recombinant human β1,4 galactosyltransferase 1 (β4GalT-1). The sugar derivatives carry short or long amino- or azide-terminated linker molecules for further modification or immobilization. The linker chemistry had an impact on enzyme kinetics and enzymatic syntheses of N-acetyllactosamine derivatives (LacNAc, Gal(β1-4)GlcNAc(β1-R). The combination of β4GalT-1 with bacterial β1,3-N-acetylglucosaminyltransferase (β3GlcNAc-T) resulted in the preparative syntheses of LacNAc oligomers with up to three LacNAc repeating units. All products were characterized by NMR and MS. The obtained LacNAc glycans were immobilized onto microtiter plates and their efficiency of binding of fungal galectin CGL2 was determined.
- Adamiak, Kathrin,Anders, Thorsten,Henze, Manja,Keul, Helmut,Moeller, Martin,Elling, Lothar
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p. 108 - 114
(2012/10/30)
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- Synthesis of a Difunctional Orthogonal Coupler for the Preparation of Carbohydrate-Functionalized sP(EO-stat-PO) Hydrogels
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The synthesis and characterization of a new difunctional coupler (4) based on trimethylolpropane (TMP) are described. The coupler is used to connect biologically active N-acetylglucosamine (GlcNAc) on amino-reactive microtiter plates and on star-shaped po
- Anders, Thorsten,Adamiak, Kathrin,Keul, Helmut,Elling, Lothar,Moeller, Martin
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p. 1201 - 1210
(2012/05/05)
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- One-step conversion of unprotected sugars to β-glycosyl azides using 2-chloroimidazolinium salt in aqueous solution
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Various β-glycosyl azides have been synthesized directly in water by the reaction of unprotected sugars and sodium azide mediated by 2-chloro-1,3-dimethylimidazolinium chloride (DMC).
- Tanaka, Tomonari,Nagai, Hikaru,Noguchi, Masato,Kobayashi, Atsushi,Shoda, Shin-Ichiro
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supporting information; experimental part
p. 3378 - 3379
(2009/12/26)
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- Bifunctional CD22 ligands use multimeric immunoglobulins as protein scaffolds in assembly of immune complexes on B cells
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CD22 is a B cell-specific sialic acid-binding immunoglobulin-like lectin (Siglec) whose function as a regulator of B cell signaling is modulated by its interaction with glycan ligands bearing the sequence NeuAcα2-6Gal. To date, only highly multivalent polymeric ligands (n = 450) have achieved sufficient avidity to bind to CD22 on native B cells. Here we demonstrate that a synthetic afunctional molecule comprising a ligand of CD22 linked to an antigen (nitrophenol; NP) can use a monoclonal anti-NP IgM as a decavalent protein scaffold to efficiently drive assembly of IgM-CD22 complexes on the surface of native B cells. Surprisingly, anti-NP antibodies of lower valency, IgA (n = 4) and IgG (n = 2), were also found to drive complex formation, though with lower avidity. Ligands bearing alternate linkers of variable length and structure were constructed to establish the importance of a minimal length requirement, and versatility in the structural requirement. We show that the ligand drives assembly of IgM complexes exclusively on the surface of B cells and not other classes of white blood cells that do not express CD22, which lends itself to the possibility of targeting B cells in certain hematopoietic malignancies.
- O'Reilly, Mary K.,Collins, Brian E.,Han, Shoufa,Liao, Liang,Rillahan, Cory,Kitov, Pavel I.,Bundle, David R.,Paulson, James C.
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p. 7736 - 7745
(2008/12/22)
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- Protecting group free glycosidations using p-toluenesulfonohydrazide donors
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(Figure Presented) N-Glycopyranosylsulfonohydrazides are introduced as glycosyl donors for protecting group free synthesis of O-glycosides, glycosyl azides, and oxazolines. Mono- and disaccharides containing a reducing terminal N-acelylglucosamine residue were condensed with p-toluenesulfonylhydrazide to give the desired β-D-pyranose donors. These donors can be activated with NBS and then glycosidated with the desired alcohol or transformed to the oxazoline or glycosyl azide.
- Gudmundsdottir, Anna V.,Nitz, Mark
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supporting information; body text
p. 3461 - 3463
(2009/04/16)
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- Chemoselective ligation of maleimidosugars to peptides/protein for the preparation of neoglycopeptides/neoglycoprotein
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Two types of maleimidosugars as thiol-selective carbohydrates, 1-maleimidosugars and acetyl-linked maleimidosugars, were efficiently synthesized. They were coupled to glutathione, Fas peptide and bovine serium albumin (BSA) to prepare the corresponding glycosylated peptides and a protein via stable thioether linkages in a chemoselective manner.
- Shin, Injae,Jung, Hyuk-Jun,Lee, Myung-Ryul
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p. 1325 - 1328
(2007/10/03)
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- Regiospecific syntheses of N-acetyllactosamine derivatives and application toward a highly practical synthesis of Lewis X trisaccharide
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An efficient methodology for regiospecific glycosylation was developed by using 6-O-tert-butyldiphenylsilyl N-acetylglucosamine derivatives 3 and 5 which bear two free hydroxyl groups as acceptors. The regiospecificity was attributed to the presence of the tert-butyldiphenylsilyl group at the O-6 position of the N-acetylglucosamine derivatives. Glycosylation of suitably protected galactoside donors 10-14 with acceptors 3 and 5 gave only β(1→4) linked disaccharides 15-19 in good yields. Fucosylation of disaccharide 18 led to Lewis X (Lex) trisaccharide 21 in high yield.
- Gan, Zhonghong,Cao, Suoding,Wu, Qingquan,Roy, Rene
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p. 755 - 773
(2007/10/03)
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- SYNTHESIS OF 2-ACETAMIDO-1-N--2-DEOXY-β-D-GLUCOPYRANOSYLAMINE AND ANALOGS
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2-Acetamido-1-N--2-deoxy-β-D-glucopyranosylamine and analogs containing D-glucopyranosyl, 4-O-β-D-glucopyranosyl-D-glucopyranosyl, L-Phe-L-Ala, and D-Phe-L-Ser were synth
- Tamura, Masahiro,Okai, Hideo
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p. 207 - 218
(2007/10/02)
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