- Single-Cell-Based Screening and Engineering of d -Amino Acid Amidohydrolases Using Artificial Amidophenol Substrates and Microbial Biosensors
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Enantiomerically pure d-amino acids are important intermediates as chiral building blocks for peptidomimetics and semisynthetic antibiotics. Here, a transcriptional factor-based screening strategy was used for the rapid screening of d-stereospecific amino acid amidase via an enzyme-specific amidophenol substrate. We used a d-threonine amidophenyl derivative to produce 2-aminophenol that serves as a putative enzyme indicator in the presence of d-threonine amidases. Comparative analyses of known bacterial species indicated that several Bacillus strains produce amidase and form putative indicators in culture media. The estimated amidase was cloned and subjected to rapid directed evolution through biosensor cells. Consequently, we characterized the F119A mutation that significantly improved the catalytic activity toward d-alanine, d-threonine, and d-glutamate. Its beneficial effects were confirmed by higher conversions and recurrent applications of the mutant enzyme, compared to the wild-type. This study showed that rapid directed evolution with biosensors coupled to designed substrates is useful to develop biocatalytic processes.
- An, Jung-Ung,Kim, Haseong,Kwon, Kil Koang,Lee, Dae-Hee,Lee, Hyewon,Lee, Jin-Young,Lee, Seung-Goo,Park, Sung Hyun,Rha, Eugene,Yeom, Soo-Jin
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p. 1203 - 1211
(2022/01/27)
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- Polyketides, diketopiperazines and an isochromanone from the marine-derived fungal strain Fusarium graminearum FM1010 from Hawaii
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The fungal strain Fusarium graminearum FM1010 was isolated from a shallow-water volcanic rock known as “live rock” at the Carl Smith Beach, Hilo, Hawaii. Eleven specialised metabolites, including two undescribed diketopiperazines, three undescribed polyketides, and one undescribed isochromanone, along with five known fusarielin derivatives were obtained from F. graminearum FM1010. The structures of the six undescribed compounds were elucidated by extensive analysis of NMR spectroscopy, HRESIMS, chemical reactions, and electronic circular dichroism (ECD) data. Kaneoheoic acids G-I showed mild inhibitory activity against S. aureus with the MIC values in the range of 20–40 μg/mL when assayed in combination with chloramphenicol (half of the MIC, 1 μg/mL), an FDA approved antibiotic. Kaneoheoic acid I exhibited both anti-proliferative activity against ovarian cancer cell line A2780 and TNF-α induced NF-κB inhibitory activity with the IC50 values of 18.52 and 15.86 μM, respectively.
- Cao, Shugeng,Sarotti, Ariel M.,Uz Zaman, KH Ahammad,Wu, Xiaohua
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- Inherently chiral dialkyloxy-calix[4]arene acetic acids as enantiodiscriminating additives for high-performance liquid chromatography separation of d,l-amino acids
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Inherently chiral dialkyloxy-calix[4]arene acetic acids with asymmetric placement of substituents on the lower rim of the macrocycle were first studied as enantiodiscriminating additives to the mobile phase MeCN/H2O/HCOOH (75/25/0.02 by volume) in the high-performance liquid chromatography (HPLC) separation of d,l-alanine and d,l-valine on the achiral stationary phase ZORBAX Original CN. The dependence of enantio-binding properties on the position of alkyl groups is demonstrated. The highest resolution (1.65) and enantioselectivity (1.80) were obtained for the 1,2-dipropyloxy-calix[4]arene acetic acid.
- Kalchenko, Olga I.,Trybrat, Oleksandr O.,Yesypenko, Oleksandr A.,Dyakonenko, Viktoriya V.,Shishkina, Svitlana V.,Kalchenko, Vitali I.
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p. 722 - 730
(2021/08/26)
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- A new amide from the marine sponge Haliclona baeri
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A new amide, baeriamide (1), along with nine known diketopiperazines (2-10), was isolated from the marine sponge Haliclona baeri. Their structures were identified by the means of UV, IR, MS and NMR. The absolute configuration of 1 was established by Marfey’s method and comparing the specific optical rotation with the known compound HCO-Val-Gly methyl ester. Compound 1 was derived from dehydration of formylated L-valine with γ-amino-butanoic acid methyl ester. Compounds 2-10 were isolated from the genus of Haliclona for the first time. The absolute confirmation of 7 was confirmed first by the means of single-crystal X-ray diffraction. The cytotoxic, antibacterial, antiviral and antifouling activities of these compounds were also tested. However, none of them exhibited significant bioactivities.
- Cui, Le-Zhi,Lei, Yu,Liao, Xiao-Jian,Wang, Can-Bin,Xiao, Yan-Fang,Xu, Jia-Yi,Xu, Shi-Hai,Zhao, Bing-Xin
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supporting information
(2021/07/06)
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- Targeted Isolation of Asperheptatides from a Coral-Derived Fungus Using LC-MS/MS-Based Molecular Networking and Antitubercular Activities of Modified Cinnamate Derivatives
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Under the guidance of MS/MS-based molecular networking, four new cycloheptapeptides, namely, asperheptatides A-D (1-4), were isolated together with three known analogues, asperversiamide A-C (5-7), from the coral-derived fungus Aspergillus versicolor. The planar structures of the two major compounds, asperheptatides A and B (1 and 2), were determined by comprehensive spectroscopic data analysis. The absolute configurations of the amino acid residues were determined by advanced Marfey's method. The two structurally related trace metabolites, asperheptatides C and D (3 and 4), were characterized by ESI-MS/MS fragmentation methods. A series of new derivatives (8-26) of asperversiamide A (5) were semisynthesized. The antitubercular activities of 1, 2, and 5-26 against Mycobacterium tuberculosis H37Ra were also evaluated. Compounds 9, 13, 23, and 24 showed moderate activities with MIC values of 12.5 μM, representing a potential new class of antitubercular agents.
- Chao, Rong,Hou, Xue-Mei,Xu, Wei-Feng,Hai, Yang,Wei, Mei-Yan,Wang, Chang-Yun,Gu, Yu-Cheng,Shao, Chang-Lun
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- Simultaneous Preparation of (S)-2-Aminobutane and d -Alanine or d -Homoalanine via Biocatalytic Transamination at High Substrate Concentration
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(S)-2-Aminobutane, d-alanine, and d-homoalanine are important intermediates for the production of various active pharmaceutical ingredients and food additives. The preparation of these small chiral amine or amino acids with high water solubility still demands searching for efficient methods. In this work, we identified an ω-transaminase (ω-TA) from Sinirhodobacter hungdaonensis (ShdTA) that catalyzed the kinetic resolution of racemic 2-aminobutane at a concentration of 800 mM using pyruvate as the amino acceptor, leading to the simultaneous isolation of enantiopure (S)-2-aminobutane and d-alanine in 46% and 90% yield, respectively. In addition, (S)-2-aminobutane (98% ee) and d-homoalanine (99% ee) were isolated in 45% and 93% yield, respectively, in the kinetic resolution of racemic 2-aminobutane at a concentration of 400 mM coupled with deamination of l-threonine by threonine deaminase. We thus developed a biocatalytic process for the practical synthesis of these valuable small chiral amine and d-amino acids.
- Li, Jianjiong,Wang, Yingang,Wu, Qiaqing,Yao, Peiyuan,Yu, Shanshan,Zhu, Dunming
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supporting information
(2022/03/01)
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- Exploration of Transaminase Diversity for the Oxidative Conversion of Natural Amino Acids into 2-Ketoacids and High-Value Chemicals
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The use of 2-ketoacids is very common in feeds, food additives, and pharmaceuticals, and 2-ketoacids are valuable precursors for a plethora of chemically diverse compounds. Biocatalytic synthesis of 2-ketoacids starting from l-amino acids would be highly desirable because the substrates are readily available from biomass feedstock. Here, we report bioinformatic exploration of a series of aminotransferases (ATs) to achieve the desired conversion. Thermodynamic control was achieved by coupling an l-glutamate oxidation reaction in the cascade for the recycling of the amine acceptor. These enzymes were able to convert a majority of proteinogenic amino acids into the corresponding 2-ketoacids with high conversion (up to 99percent) and atom-efficiency. Furthermore, this enzyme cascade was extendable, and one-pot two-step processes were established for the synthesis of d-amino acids and N-methylated amino acids, achieving great overall conversion (up to 99percent) and high ee values (>99percent). These developed enzymatic methodologies offer convenient routes for utilizing amino acids as synthetic reagents.
- Chen, Yanchun,Cui, Xuexian,Cui, Yinglu,Li, Chuijian,Li, Ruifeng,Li, Tao,Sun, Jinyuan,Wu, Bian,Zhu, Tong
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p. 7950 - 7957
(2020/08/21)
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- Krisynomycins, Imipenem Potentiators against Methicillin-Resistant Staphylococcus aureus, Produced by Streptomyces canus
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A reinvestigation of the acetone extract of the strain CA-091830 of Streptomyces canus, producer of the imipenem potentiator krisynomycin, resulted in the isolation of two additional analogues, krisynomycins B (1) and C (2), with different chlorination patterns. Genome sequencing of the strain followed by detailed bioinformatics analysis led to the identification of the corresponding biosynthetic gene cluster (BGC) of this cyclic nonribosomal peptide family. The planar structure of the new molecules was determined using HRMS, ESI-qTOF-MS/MS, and 1D and 2D NMR data. Their absolute configuration was proposed using a combination of Marfey's and bioinformatic BGC analyses. The krisynomycins displayed weak to negligible antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), which was significantly enhanced when tested in combination with sublethal concentrations of imipenem. The halogenation pattern plays a key role in the antimicrobial activity and imipenem-potentiating effects of the compounds, with molecules having a higher number of chlorine atoms potentiating the effect of imipenem at lower doses.
- De La Cruz, Mercedes,Genilloud, Olga,González, Ignacio,Martín, Jesús,Oves-Costales, Daniel,Pérez-Bonilla, Mercedes,Reyes, Fernando,Vicente, Francisca
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p. 2597 - 2606
(2020/10/12)
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- Homogeneous palladium-catalyzed enantioselective hydrogenation of 5-methylenhydantoin for the synthesis of L-Valine
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In this article, we present the development of a synthetic methodology based on homogeneous catalysis for the preparation of enantioenriched L-Valine aminoacid. The enantioselective hydrogenation of 5-methylenhydantoin has been developed through broad screenings of chiral ligands, metal precursors and reaction conditions including scale-up experiments and recyclability studies. A palladium catalyzed asymmetric hydrogenation of 5-methylenhydantoin afforded the corresponding hydrogenated product in a 70% enantiomeric excess using a substrate/catalyst ratio of 500/1. A partial racemization was observed upon hydrolysis and recovery of L-Valine.
- Agbossou-Niedercorn, Francine,Bellière-Baca, Virginie,Hayouni, Safa,Michon, Christophe,Morvan, Didier
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supporting information
(2020/10/18)
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- Preparation and characterization of a new open-tubular capillary column for enantioseparation by capillary electrochromatography
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In order to use the enantioseparation capability of cationic cyclodextrin and to combine the advantages of capillary electrochromatography (CEC) with open-tubular (OT) column, in this study, a new OT-CEC, coated with cationic cyclodextrin (1-allylimidazolium-β-cyclodextrin [AI-β-CD]) as chiral stationary phase (CSP), was prepared and applied for enantioseparation. Synthesized AI-β-CD was characterized by infrared (IR) spectrometry and mass spectrometry (MS). The preparation conditions for the AI-β-CD-coated column were optimized with the orthogonal experiment design L9(34). The column prepared was characterized by scanning electron microscopy (SEM) and elemental analysis (EA). The results showed that the thickness of stationary phase in the inner surface of the AI-β-CD-coated columns was about 0.2 to 0.5?μm. The AI-β-CD content in stationary phase based on the EA was approximately 2.77?mmol·m?2. The AI-β-CD-coated columns could separate all 14 chiral compounds (histidine, lysine, arginine, glutamate, aspartic acid, cysteine, serine, valine, isoleucine, phenylalanine, salbutamol, atenolol, ibuprofen, and napropamide) successfully in the study and exhibit excellent reproducibility and stability. We propose that the column, coated with AI-β-CD, has a great potential for enantioseparation in OT-CEC.
- Li, Yingjie,Tang, Yimin,Qin, Shili,Li, Xue,Dai, Qiang,Gao, Lidi
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p. 283 - 292
(2019/02/05)
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- Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce
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Pseudomonas cichorii, which causes varnish spots on lettuce and seriously damages lettuce production during the summer season in the highland areas of Japan (e.g., Nagano and Iwate prefectures) was isolated. The structure of a toxin produced by this organism was analyzed based on the detailed evaluation of its 2D NMR and FABMS spectra, and this compound has not been reported previously. We propose the name cichorinotoxin for this toxin. In conjunction with the D or L configurations of each amino acid, which were determined by Marfey’s method, we propose the structure of cichorinotoxin to be as follows: 3-hydroxydecanoyl-(Z)-dhThr1-D-Pro2-D-Ala3-D-Ala4-D-Ala5-D-Val6-D-Ala7-(Z)-dhThr8-Ala9-Val10-D-Ile11-Ser12-Ala13-Val14-Ala15-Val16-(Z)-dhThr17-D-alloThr18-Ala19-L-Dab20-Ser21-Val22, and an ester linkage is present between D-alloThr18 and Val22 (dhThr: 2-aminobut-2-enoic acid; Dab: 2,4-diaminobutanoic acid). Thus, the toxin is a lipodepsipeptide with 22 amino acids. The mono- and tetraacetate derivatives and two alkaline hydrolysates, compounds A and B, were prepared. We discuss here the structure–activity relationships between the derivatives and their necrotic activities toward lettuce.
- Komatsu, Hidekazu,Shirakawa, Takashi,Uchiyama, Takeo,Hoshino, Tsutomu
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p. 299 - 309
(2019/02/20)
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- Artificial Biocatalytic Cascade with Three Enzymes in One Pot for Asymmetric Synthesis of Chiral Unnatural Amino Acids
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Two biocatalytic reactions, transamination catalyzed by transaminases and reductive amination catalyzed by amino acid dehydrogenases, can be used for asymmetric synthesis of optically pure unnatural amino acids. However, although transaminases show a great diversity and broad substrate spectrum, most transaminase reactions are reversible, while amino acid dehydrogenases catalyze reductive amination irreversibly but with strict substrate specificity. Accordingly, herein we developed a tri-enzyme one-pot reaction system to exploit the respective advantages of transaminases and amino acid dehydrogenases, while overcoming the disadvantages of each. In this work, representatives of all four subgroups of transaminases coupled with different amino acid dehydrogenases to produce five l- and four d- unnatural amino acid products, using ammonia and the co-enzyme NAD(P)H, which is regenerated by a robust alcohol dehydrogenase with 2-propanol as cheap cosubstrate. The complete conversion and high enantiopurity (ee > 99 %) of the products, demonstrated it as an ideal alternative for asymmetric synthesis of chiral amino acid compounds.
- Zhou, Haisheng,Meng, Lijun,Yin, Xinjian,Liu, Yayun,Xu, Gang,Wu, Jianping,Wu, Mianbin,Yang, Lirong
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supporting information
p. 6470 - 6477
(2019/11/02)
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- Complex-precipitation using functionalized chiral ionic liquids with L-proline anion and chromatographic analysis for enantioseparation of racemic amino acids
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As one kind of functionalized green medium, chiral ionic liquids (CILs) have been widely applied in fields of asymmetric catalysis, enantioseparation, and so on. In this study, four kinds of amino acid–based CILs were synthesized by using trimethylamine, N-methylpyrrolidine, N-methylimidazole, and tropine as cationic nucleus, respectively. Then their specific optical rotation and solubility in common solvents were determined for further resolution application. The effect of different cations in these CILs was explored on the separation of racemic phenylalanine in complex-precipitation way. Moreover, various factors were systematically investigated for their effects on resolution efficiency, including the type of additive copper salts, the molar ratio of Cu (II) to CIL, pH value, the amount of racemic phenylalanine, and temperature. Under the appropriate conditions, L-phenylalanine mainly existed in solid phase and could be separated from its enantiomers in liquid phase. Furthermore, the mechanism of resolution was studied by thermogravimetric analysis, infrared spectrum, and molecular simulation. The resolution system has characteristics of no organic solvent, fast separation speed, simple resolution process, and easy scale-up.
- Zang, Huimin,Yao, Shun,Luo, Yingjie,Tang, Dan,Song, Hang
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p. 1182 - 1194
(2018/09/12)
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- Accessing d-Valine Synthesis by Improved Variants of Bacterial Cyclohexylamine Oxidase
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Chemoenzymatic deracemization was applied to prepare d-valine from racemic valine ethyl ester or l-valine ethyl ester in high yield (up to 95 %) with excellent optical purity (>99 % ee) by employing a newly evolved cyclohexylamine oxidase (CHAO) variant Y321I/M226T exhibiting catalytic efficiency that was 30 times higher than that of the wildtype CHAO. Interestingly, CHAO and its variants showed opposite enantioselectivity for valine ethyl ester and phenylalanine ethyl ester.
- Gong, Rui,Yao, Peiyuan,Chen, Xi,Feng, Jinhui,Wu, Qiaqing,Lau, Peter C. K.,Zhu, Dunming
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p. 387 - 390
(2017/12/26)
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- Structure-guided engineering of: Meso -diaminopimelate dehydrogenase for enantioselective reductive amination of sterically bulky 2-keto acids
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meso-Diaminopimelate dehydrogenase (DAPDH) and mutant enzymes are an excellent choice of biocatalysts for the conversion of 2-keto acids to the corresponding d-amino acids. However, their application in the enantioselective reductive amination of bulky 2-keto acids, such as phenylglyoxylic acid, 2-oxo-4-phenylbutyric acid, and indole-3-pyruvic acid, is still challenging. In this study, the structure-guided site-saturation mutagenesis of a Symbiobacterium thermophilum DAPDH (StDAPDH) gave rise to a double-site mutant W121L/H227I, which showed dramatically improved enzyme activities towards various 2-keto acids including these sterically bulky substrates. Several d-amino acids were prepared in optically pure form. The molecular docking of substrates into the active sites of wild-type and mutant W121L/H227I enzymes revealed that the substrate binding cavity of the mutant enzyme was reshaped to accommodate these bulky substrates, thus leading to higher enzyme activity. These results lay a foundation for further shaping the substrate binding pocket and manipulating the interactions between the substrate and binding sites to access highly active d-amino acid dehydrogenases for the preparation of synthetically challenging d-amino acids.
- Cheng, Xinkuan,Chen, Xi,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
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p. 4994 - 5002
(2018/10/17)
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- Chromatographic Resolution of α-Amino Acids by (R)-(3,3'-Halogen Substituted-1,1'-binaphthyl)-20-crown-6 Stationary Phase in HPLC
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Three new chiral stationary phases (CSPs) for high-performance liquid chromatography were prepared from R-(3,3'-halogen substituted-1,1'-binaphthyl)-20-crown-6 (halogen = Cl, Br and I). The experimental results showed that R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 (CSP-1) possesses more prominent enantioselectivity than the two other halogen-substituted crown ether derivatives. All twenty-one α-amino acids have different degrees of separation on R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6-based CSP-1 at room temperature. The enantioselectivity of CSP-1 is also better than those of some commercial R-(1,1'-binaphthyl)-20-crown-6 derivatives. Both the separation factors (α) and the resolution (Rs) are better than those of commercial crown ether-based CSPs [CROWNPAK CR(+) from Daicel] under the same conditions for asparagine, threonine, proline, arginine, serine, histidine and valine, which cannot be separated by commercial CR(+). This study proves the commercial usefulness of the R-(3,3'-dibromo-1,1'-binaphthyl)-20-crown-6 chiral stationary phase.
- Wu, Peng,Wu, Yuping,Zhang, Junhui,Lu, Zhenyu,Zhang, Mei,Chen, Xuexian,Yuan, Liming
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supporting information
p. 1037 - 1042
(2017/07/25)
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- Visible-light photoredox-catalyzed desulfurization of thiol- and disulfide-containing amino acids and small peptides
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A scalable protocol for the desulfurization of cysteine by using visible light, the photocatalyst Ir(dF(CF3)ppy)2(dtb-bpy)PF6 and triethylphosphite under biphasic reaction conditions has been developed. The loading of the catalyst can be as low as 0.01?mol%, which can be efficiently removed during the workup (≤0.3?ppm), giving rise to the corresponding desulfurized product in high yields. This method has been applied also to cystine, penicillamine, and reduced and oxidized glutathione. The desulfurization has been found to be pH sensitive, with an optimal pH value of 6.5 and 7.0 for the cysteine derivatives and glutathione, respectively. In addition, during the desulfurization of a decapeptide containing cysteine and methionine, concurrent oxidation of the two sulfur-containing residues to disulfide and sulfoxide has been observed. Therefore, whereas the presented protocol allows a straightforward visible light-mediated desulfurization of simple thiols by using very low catalyst loading and a cost-effective trialkylphosphite as thiyl radical trapping agent, its application to complex substrates needs to be carefully validated. Copyright
- Lee, Myungmo,Neukirchen, Saskia,Cabrele, Chiara,Reiser, Oliver
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p. 556 - 562
(2017/08/14)
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- The asymmetric reduction of imidazolinones with trichlorosilane
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It is shown how imidazolinones are reduced by trichlorosilane in a highly enantioselective fashion when treated with a novel Lewis base organocatalyst that is based on a 2,2′-bispyrrolidine core. Under mild reaction conditions and with low catalyst loading the hydrosilylation reaction provides a broad range of chiral imidazolidinones with various structural motifs including sterically demanding substituents, alkyls and aryls.
- Wagner, Christian,Kotthaus, Andreas F.,Kirsch, Stefan F.
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supporting information
p. 4513 - 4516
(2017/04/26)
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- The optical activity of the valine compound and its production method
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The invention relates to an optically active valine compound and a production method thereof. The optically active valine compound is composed of 1 mole of L-valine and 1 mole of N-benzoyl-L-alanine. The production method comprises the steps of reacting the N-benzoyl-L-alanine selectively with L-valine in the presence of D-valine, other amino acids, impurities generated in the DL-valine synthesis process and a crude product L-valine obtained by hydrolyzing or fermenting proteins, thereby forming a novel crystal compound. The optically active L-valine and N-benzoyl-L-alanine can be taken as intermediates for optically decomposing DL-valine and purifying L-valine.
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-
Paragraph 0059; 0060; 0061; 0062; 0063; 0065; 0066
(2017/04/21)
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- New compounds from a hydrothermal vent crab-associated fungus Aspergillus versicolor XZ-4
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Three new quinazoline derivatives (1-3), one new oxepin-containing natural product (4) and four new cyclopenin derivatives (5-7 and 9) have been isolated from an EtOAc extract of the Taiwan Kueishantao hydrothermal vent crab-associated fungus Aspergillus versicolor XZ-4. Their planar structures were established by HRMS, 1D and 2D NMR spectroscopic data analyses. The absolute configurations for compounds 1 and 4 were determined by chiral phase HPLC analysis of their hydrolysis products. The absolute configurations of 2, 3 and 7 were defined mainly by comparison of the quantum chemical TDDFT calculated and the experimental ECD spectra, and the absolute configuration of 5 was deduced from comparison of the optical rotation values reported in the literature. The presence of two atropisomers of 5 was established by NOE analyses. The Ile & Val units in compounds 1-3 allowed the assignment of a new quinazoline skeleton and it's the first time the configuration of isoleucine in the quinazoline skeleton was defined. A series of 7-methoxy cyclopenin derivatives were reported for the first time in this study. The bioevaluation of compounds 5, 7, 8 and 9 revealed inhibitory activities against E. coli at MIC values around 32 μg mL?1
- Pan, Chengqian,Shi, Yutong,Chen, Xuegang,Chen, Chen-Tung Arthur,Tao, Xinyi,Wu, Bin
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p. 1155 - 1163
(2017/02/10)
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- Neopeapyran, an unusual furo[2,3b]pyran analogue and turnagainolide C from a soil Streptomyces sp. S2236
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Neopeapyran (1), an unusual furo[2,3b]pyran analogue, together with a new cyclopeptide, turnagainolide C (2), were isolated from Streptomyces sp. S2236 associated with the rhizosphere soil of Panax notoginseng. The planar structure and relative configuration of neopeapyran (1) were elucidated on the basis of spectroscopic techniques, while the absolute configuration was determined by TDDFT calculation. The absolute configuration of turnagainolide C (2) was determined by partial hydrolysis, together with the advanced Marfey's method and spectroscopic analysis. The antimicrobial activities of these two compounds were also investigated.
- Zhou, Hao,Yang, Ya-Bin,Duan, Rong-Ting,Yang, Xue-Qiong,Zhang, Ju-Cheng,Xie, Xiao-Guang,Zhao, Li-Xing,Ding, Zhong-Tao
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supporting information
p. 1044 - 1047
(2016/07/29)
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- Optically active valine complex and a method for producing the same
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The present invention discloses an optically active complex of L-valine N-benzoyl-L-alanine, comprising one mole each of L-valine and N-benzoyl-L-alanine. N-benzoyl-L-alanine is found to react selectively with L-valine to form the novel crystalline complex even in the presence of D-valine, other amino acids, and impurities present in synthetic DL-valine and in the crude L-valine from the hydrolysis of protein and fermentation. The optically active L-valine N-benzoyl-L-alanine is used as an intermediate for the optical resolution of DL-valine and for the purification of L-valine.
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- ｔ-BUTYLKETONE BINAPHTHOL DERIVATIVES AND PREPARING METHOD THEREOF
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The present disclosure relates to a t-butylketone binaphthol derivative and a method of preparing the same, the t-butylketone binaphthol derivative being a high-efficiency chiral extracting agent which has a very high chiral selectivity enabling to extract an amino acid from an aqueous solution phase to an organic layer and to facilitate its hydrolysis, and enabling a continuous reuse of the organic layer.
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Page/Page column 0097
(2017/01/17)
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- Efficient synthesis of chiral binaphthol aldehyde with phenyl ether linkage for enantioselective extraction of amino acids
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A binaphthol aldehyde with phenyl ether linkage, compound 2, has been synthesized starting from binaphthol-3-carboxylic acid. The axially chiral binaphthol ring was racemized during the synthesis due to high temperatures required in O-phenylation reaction. The enantiomerically pure form of 2 was obtained from the resolution of the diastereomeric imine of 2. Optically pure compound (S)-2 was applied to the enantioselective liquid-liquid extraction of amino acid between CH2Cl2 and aqueous layers.The stereoselectivities, that is, D/L ratio of the amino acid extracted, ranged from 3.57 to 11.1. One carbon was absent in compound (S)-2 compared to the compound (S)-1 with benzyl ether linkage, which differentiated the conformations of their imines formed with amino acids.
- Choi, Misun,Jun, Moo-Jin,Kim, Kwan Mook
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p. 1834 - 1837
(2015/07/15)
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- Enantiomeric separation of underivatized amino acids: Predictability of chiral recognition on ristocetin a chiral stationary phase
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The present work aimed to investigate the predictability of the chromatographic behavior for the separation of underivatized amino acids on ristocetin A, known as Chirobiotic R, using a DryLab high-performance liquid chromatography (HPLC) method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. After implementing the basic runs, and judging the predictability via the computed resolution map, it can be deduced that the chiral recognition mechanisms tend towards a hydrophilic interaction chromatography rather than the reversed phase mode, which limits the ability of DryLab software to predict separations on Chirobiotic R.
- Wagdy, Hebatallah A.,Hanafi, Rasha S.,El-Nashar, Rasha M.,Aboul-Enein, Hassan Y.
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p. 132 - 135
(2014/03/21)
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- Modification of cellulose acetates for preparing chiral sorbents
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Modification of cellulose acetates via sorption-desorption of vapors of mesogenic solvents in which the polymer forms a lyotropic liquid crystal phase and of mixtures of these solvents with water leads to the formation of a new chiral structure of the polymeric sample. This is manifested in a significant change in the value and even sign of the specific optical rotation of the polysaccharide system. The sorbents based on cellulose acetates that have been modified by such treatment exhibit specific affinity for definite optical antipodes. When a racemic mixture of L- and D-isomers of amino acids is passed through this sorbent, it acts as a chiral filter owing to "steric recognition" of one of the enantiomers, so that the filtrate contains an optically pure product (isomer). The revealed effects served as a basis for the development of a new procedure for preparation of optically pure stereoisomers of chiral products.
- Shipovskaya,Gegel',Shchegolev
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p. 1326 - 1333
(2015/05/20)
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- Trichormamides A and B with antiproliferative activity from the cultured freshwater cyanobacterium Trichormus sp. UIC 10339
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Two new cyclic lipopeptides, trichormamides A (1) and B (2), were isolated from the cultured freshwater cyanobacterium Trichormus sp. UIC 10339. The strain was obtained from a sample collected in Raven Lake in Northern Wisconsin. The planar structures of trichormamides A (1) and B (2) were determined using a combination of spectroscopic analyses including HRESIMS and 1D and 2D NMR experiments. The absolute configurations of the amino acid residues were assigned by the advanced Marfey's method after acid hydrolysis. Trichormamide A (1) is a cyclic undecapeptide containing two d-amino acid residues (d-Tyr and d-Leu) and one β-amino acid residue (β-aminodecanoic acid). Trichormamide B (2) is a cyclic dodecapeptide characterized by the presence of four nonstandard α-amino acid residues (homoserine, N-methylisoleucine, and two 3-hydroxyleucines) and one β-amino acid residue (β-aminodecanoic acid). Trichormamide B (2) was cytotoxic against MDA-MB-435 and HT-29 cancer cell lines with IC50 values of 0.8 and 1.5 μM, respectively.
- Luo, Shangwen,Krunic, Aleksej,Kang, Hahk-Soo,Chen, Wei-Lun,Woodard, John L.,Fuchs, James R.,Swanson, Steven M.,Orjala, Jimmy
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p. 1871 - 1880
(2014/10/16)
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- SEPARATING AGENT AND MANUFACTURING METHOD THEREOF
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An embodiment of the present invention is a separating agent wherein a group represented by a chemical formula of: or a group represented by a chemical formula of: is introduced on a surface thereof.
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Paragraph 0067; 0068; 0069; 0070; 0071; 0072; 0079; 0080
(2015/01/07)
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- A new prenylated indole diketopiperazine alkaloid from Eurotium cristatum
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A new prenylated indole diketopiperazine alkaloid, cristatumin F (1), and four known metabolites, echinulin (2), dehydroechinulin (3), neoechinulin A (4) and variecolorin O ( 5), were isolated from the crude extract of the fungus Eurotium cristatum. The structure of 1 was elucidated primarily by NMR and MS methods. The absolute configuration of 1 was assigned using Marfey's method applied to its acid hydrolyzate. Cristatumin F (1) showed modest radical scavenging activity against DPPH radicals, and exhibited marginal attenuation of 3T3L1 pre-adipocytes.
- Zou, Xianwei,Li, Ying,Zhang, Xiaona,Li, Qian,Liu, Xuan,Huang, Yun,Tang, Tao,Zheng, Saijing,Wang, Weimiao,Tang, Jintian
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p. 17839 - 17847
(2015/03/04)
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- Chiral cationic polyamines for chiral microcapsules and siRNA delivery
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Reported herein is the use of chiral cationic polyamines for two intriguing applications: fabrication of chiral covalently-linked microcapsules, and enantiospecific delivery of siRNA to Huh 7 cells. The microcapsules are easily fabricated from homochiral polymers, and the resulting architectures can be used for supramolecular chiral catalysis and many other potential applications. Enantiospecific delivery of siRNA to Huh 7 cells is seen by one 'enantiomer' of the polymers delivering siRNA with significantly improved transfection efficiency and reduced toxicity compared to the 'enantiomeric' polymer and commercially available transfection reagents. Taken together, the use of these easily accessible polyamine structures for diverse applications is highlighted in this Letter herein and can lead to numerous future research efforts.
- Gharavi, Justin,Marks, Patrick,Moran, Kelly,Kingsborough, Brett,Verma, Ruchi,Chen, Yuan,Deng, Ruitang,Levine, Mindy
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supporting information
p. 5919 - 5922
(2013/10/22)
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- SEPARATING AGENT FOR CHROMATOGRAPHY
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A separating agent for chromatography is provided that is useful for the separation of specific compounds, e.g., for the optical resolution of amino acids. This separating agent for chromatography provides a higher productivity and contains a crown ether-like cyclic structure and optically active binaphthyl. This separating agent for chromatography containing a crown ether-like cyclic structure and optically active binaphthyl is provided by introducing a substitution group for binding to carrier into a specific commercially available 1,1′-binaphthyl derivative that has substituents at the 2, 2′, 3, and 3′ positions, then introducing a crown ether-like cyclic structure, and subsequently chemically bonding the binaphthyl derivative to the carrier through the substitution group for binding to carrier.
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Paragraph 0074; 0075
(2013/08/15)
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- Characterization of d-amino acid aminotransferase from Lactobacillus salivarius
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We searched a UniProt database of lactic acid bacteria in an effort to identify d-amino acid metabolizing enzymes other than alanine racemase. We found a d-amino acid aminotransferase (d-AAT) homologous gene (UniProt ID: Q1WRM6) in the genome of Lactobacillus salivarius. The gene was then expressed in Escherichia coli, and its product exhibited transaminase activity between d-alanine and α-ketoglutarate. This is the first characterization of a d-AAT from a lactic acid bacterium. L. salivarius d-AAT is a homodimer that uses pyridoxal-5′-phosphate (PLP) as a cofactor; it contains 0.91 molecules of PLP per subunit. Maximum activity was seen at a temperature of 60 °C and a pH of 6.0. However, the enzyme lost no activity when incubated for 30 min at 30 °C and pH 5.5 to 9.5, and retained half its activity when incubated at pH 4.5 or 11.0 under the same conditions. Double reciprocal plots of the initial velocity and d-alanine concentrations in the presence of several fixed concentrations of α-ketoglutarate gave a series of parallel lines, which is consistent with a Ping-Pong mechanism. The Km values for d-alanine and α-ketoglutarate were 1.05 and 3.78 mM, respectively. With this enzyme, d-allo-isoleucine exhibited greater relative activity than d-alanine as the amino donor, while α-ketobutylate, glyoxylate and indole-3-pyruvate were all more preferable amino acceptors than α-ketoglutarate. The substrate specificity of L. salivarius d-AAT thus differs greatly from those of the other d-AATs so far reported.
- Kobayashi, Jyumpei,Shimizu, Yasuhiro,Mutaguchi, Yuta,Doi, Katsumi,Ohshima, Toshihisa
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- Biocatalytic asymmetric synthesis of unnatural amino acids through the cascade transfer of amino groups from primary amines onto keto acids
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Flee to the hills: An unfavorable equilibrium in the amino group transfer between amino acids and keto acids catalyzed by α-transaminases was successfully overcome by coupling with a ω-transaminase reaction as an equilibrium shifter, leading to efficient asymmetric synthesis of diverse unnatural amino acids, including L-tert-leucine and D-phenylglycine. Copyright
- Park, Eul-Soo,Dong, Joo-Young,Shin, Jong-Shik
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p. 3538 - 3542
(2014/01/06)
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- Aniquinazolines A-D, four new quinazolinone alkaloids from marine-derived endophytic fungus aspergillus nidulans
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Four new quinazolinone alkaloids, namely, aniquinazolines A-D (1-4), were isolated and identified from the culture of Aspergillus nidulans MA-143, an endophytic fungus obtained from the leaves of marine mangrove plant Rhizophora stylosa. The structures of the new compounds were elucidated by spectroscopic analysis, and their absolute configurations were determined on the basis of chiral HPLC analysis of the acidic hydrolysates. The structure for 1 was confirmed by single-crystal X-ray diffraction analysis. All these compounds were examined for antibacterial and cytotoxic activity as well as brine shrimp (Artemia salina) lethality.
- An, Chun-Yan,Li, Xiao-Ming,Li, Chun-Shun,Wang, Ming-Hui,Xu, Gang-Ming,Wang, Bin-Gui
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p. 2682 - 2694
(2013/08/23)
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- Surugamides A-E, cyclic octapeptides with four D-amino acid residues, from a marine streptomyces sp.: LC-MS-aided inspection of partial hydrolysates for the distinction of D- and L-amino acid residues in the sequence
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Surugamides A-E (1-5), cyclic octapeptides with four d-amino acid residues, were isolated from the broth of marine-derived Streptomyces sp. Their planar structures were determined by analyses of spectroscopic data, and the absolute configuration of constituent amino acid residues was determined by the Marfey's method. Differentiation of d-Ile and l-Ile in the sequence was established by chiral analysis of fragment peptides obtained from the partial hydrolysate, whose identification was conducted by LC-MS/MS.
- Takada, Kentaro,Ninomiya, Akihiro,Naruse, Masato,Sun, Yi,Miyazaki, Masayuki,Nogi, Yuichi,Okada, Shigeru,Matsunaga, Shigeki
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p. 6746 - 6750
(2013/07/26)
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- Polymer-supported enantioselective bifunctional catalysts for nitro-Michael addition of ketones and aldehydes
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Introduction of an L-amino acid as a spacer and a urea-forming moiety in a polymer-supported bifunctional urea-primary amine catalyst, based on (1R, 2R)-(+)-1,2-diphenylethylenediamine, significantly improves the catalyst's activity and stereoselectivity in the asymmetric addition of ketones and aldehydes to nitroolefins. Yields and enantioselectivities, unprecedented for immobilized catalysts, were obtained with such challenging donors as acetone, cyclopentanone, and α,α-disubstituted aldehydes, which usually perform inadequately in this reaction (particularly when a secondary-amine-based catalyst is used). Remarkably, though in the examined catalysts the D-amino acids as spacers were significantly inferior to the L isomers, for the chosen configuration of the diamine (match-mismatch pairs) the size of the side chain of the amino acid hardly influenced the enantioselectivity of the catalyst. These results, combined with the reactivity profile of the catalysts with substrates bearing two electron-withdrawing groups and the behavior of the catalysts' analogues based on tertiary (rather than primary) amine, suggest an enamine-involving addition mechanism and a particular ordered C-C bond-forming transition state as being responsible for the catalytic reactions with high enantioselectivity. Copyright
- Tuchman-Shukron, Lital,Miller, Scott J.,Portnoy, Moshe
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body text
p. 2290 - 2296
(2012/03/27)
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- Isolation and characterization of two novel antibacterial cyclic hexapeptides from streptomyces alboflavus 313
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Two novel cyclic hexapeptides, designated NW-G08 (1) and NW-G09 (2), were isolated from the fermentation broth of Streptomyces alboflavus 313. Their structures were elucidated on the basis of extensive spectroscopic analysis, MS experiments, and chemical
- Ji, Zhiqin,Qiao, Gang,Wei, Shaopeng,Fan, Lixia,Wu, Wenjun
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p. 1567 - 1578
(2012/10/29)
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- METHOD FOR OBTAINING OPTICALLY PURE AMINO ACIDS
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This invention relates to a method for obtaining optically pure amino acids, including optical resolution and optical conversion. This method significantly shortens the time taken for optical transformation, and enables the repeated use of an organic solution containing a enantioselective receptor, to thereby obtain optically pure amino acids in a simple and remarkably efficient manner, and to enable the very economical mass production of optically pure amino acids.
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Page/Page column 7
(2012/02/01)
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- METHOD FOR OBTAINING OPTICALLY PURE AMINO ACIDS
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This invention relates to a method for obtaining optically pure amino acids, including optical resolution and optical conversion. This method significantly shortens the time taken for optical transformation, and enables the repeated use of an organic solution containing a enantioselective receptor, to thereby obtain optically pure amino acids in a simple and remarkably efficient manner, and to enable the very economical mass production of optically pure amino acids.
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Page/Page column 10-11
(2012/02/14)
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- Bromine-and chlorine-containing aeruginosins from microcystis aeruginosa bloom material collected in Kibbutz Geva, Israel
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Five new natural products, aeruginosins GE686 (1), GE766 (2), GE730 (3), GE810 (4), and GE642 (5), were isolated along with four known aeruginosins, 98C, 101, KY642, and DA688, from bloom material of the cyanobacterium Microcystis aeruginosa collected from a fish pond in Kibbutz Geva, Israel, in August 2007. Their structures were elucidated by a combination of various spectroscopic techniques, primarily NMR and MS, while the absolute configurations of the stereogenic centers were determined by Marfey's and chiral-phase HPLC methods. Two of the new aeruginosins, aeruginosins GE686 (1) and GE766 (2), contain the unprecedented d-m-Br-m′-Cl-p-hydroxyphenyllactic acid derivative. The structures and biological activities of the five new metabolites are described.
- Elkobi-Peer, Shira,Faigenbaum, Raya,Carmeli, Shmuel
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p. 2144 - 2151
(2013/02/25)
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- Cristatumins A-D, new indole alkaloids from the marine-derived endophytic fungus Eurotium cristatum EN-220
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Four new indole alkaloids, namely, cristatumins A-D (1-4), along with six known congeners (5-10) were identified from the culture extract of Eurotium cristatum EN-220, an endophytic fungus isolated from the marine alga Sargassum thunbergii. The structures of these compounds were established on the basis of extensive spectroscopic analysis. Each of these compounds was evaluated for antimicrobial and insecticidal activity. Compounds 1 and 9 showed antibacterial activity against Escherichia coli and Staphyloccocus aureus, respectively, while compounds 2, 6, and 7 exhibited moderate lethal activity against brine shrimp. Preliminary structure-activity relationships were also discussed.
- Du, Feng-Yu,Li, Xiao-Ming,Li, Chun-Shun,Shang, Zhuo,Wang, Bin-Gui
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supporting information; experimental part
p. 4650 - 4653
(2012/08/07)
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- Chiral imprinting with amino acids of ordered mesoporous silica exhibiting enantioselectivity after calcination
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Chiral ordered mesoporous silica (COMS) was synthesized in basic media by combining tetraethyl orthosilicate and quaternized aminosilane (with a templating role) silica sources together with four different standard amino acids (arginine, histidine, isoleucine, and proline). Besides the hexagonal MCM-41-type structure, narrow pore size distribution, and high specific surface area, it was found that these solids have potential for enantiomeric separation because of the transference of chirality from the amino acid to the silica. This is illustrated by the resolution of several racemic mixtures (those of proline, isoleucine, trans-4-hydroxyproline, pipecolic acid, valine, leucine, and phenylglycine) with the calcined COMS prepared with l-proline. The opposite behavior observed in induced circular dichroism experiments with calcined COMS, obtained using both enantiomers of proline, confirmed their chiral nature. The high number and variety of existing amino acids, and chiral organic compounds in general, makes these ordered silicas attractive for the production of enantiopure substances.(Figure Presented)
- Lacasta, Susana,Sebastian, Victor,Casado, Clara,Mayoral, Alvaro,Romero, Pilar,Larrea, Angel,Vispe, Eugenio,Lopez-Ram-De-Viu, Pilar,Uriel, Santiago,Coronas, Joaquin
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scheme or table
p. 1280 - 1287
(2012/02/15)
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- Dynamic kinetic resolution of α-aminonitriles to form chiral α-amino acids
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We have succeeded in the enzymatic synthesis of (R)-α-aminobutyric acid from racemic α-aminobutyronitrile. This has been demonstrated by the use of non-stereoselective nitrile hydratase (NHase) from Rhodococcus opacus 71D, D-aminopeptidase from Ochrobactrum anthropi C1-38 and α-amino-ε- caprolactam (ACL) racemase from Achromobacter obae. Racemic α- aminobutyronitrile was completely converted in 6 h at 30 °C to (R)-α-aminobutyric acid whose optical purity was more than 99%. (S)-α-Aminobutyric acid was also synthesized from α- aminobutyronitrile by NHase, ACL racemase and L-amino acid amidase from Brevundimonas diminuta TPU 5720. In a similar manner, other (R)- or (S)-α-amino acids with more than 97.5% ee could be synthesized from the corresponding α-aminonitriles. This is the first report on the dynamic kinetic resolution (DKR) of α-aminonitriles to form chiral α-amino acids. The key enzyme in this DKR is non-stereoselective NHase, which had been newly screened from soil samples, and its gene cloned. Copyright
- Yasukawa, Kazuyuki,Hasemi, Ryuji,Asano, Yasuhisa
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scheme or table
p. 2328 - 2332
(2011/10/19)
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- Aminolytic reaction catalyzed by d-stereospecific amidohydrolases from Streptomyces spp
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From investigation of 2000 soil isolates, we identified two serine-type amidohydrolases that can hydrolyze d-aminoacyl derivatives from the culture supernatant of Streptomyces species 82F2 and 83D12. The enzymes, redesignated as 82F2-DAP and 83D12-DAP, were purified for homogeneity and characterized. Each enzyme had molecular mass of approximately 40 kDa, and each showed moderate stability with respect to temperature and pH. Among hydrolytic activities toward d-aminoacyl-pNAs, the enzymes showed strict specificity toward d-Phe-pNA, but showed broad specificity toward d-aminoacyl esters. The specific activity for d-Phe-pNA hydrolysis of 82F2-DAP was ten-fold higher than that of 83D12-DAP. As a second function, each enzyme showed peptide bond formation activity by its function of aminolysis reaction. Based on results of d-Phe-d-Phe synthesis under various conditions, we propose a reaction mechanism for d-Phe-d-Phe production. Furthermore, the enzymes exhibited peptide elongation activity, producing oligo homopeptide in a one-pot reaction. We cloned the genes encoding each enzyme, which revealed that the primary structure of each enzyme showed 30-60% identity with those of peptidases belonging to the clan SE, S12 peptidase family categorized as serine peptidase with d-stereospecificity.
- Arima, Jiro,Ito, Hitomi,Hatanaka, Tadashi,Mori, Nobuhiro
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experimental part
p. 1460 - 1469
(2012/01/12)
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- New diketopiperazine derivatives isolated from sea urchin-derived Bacillus sp.
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Two new diketopiperazine derivatives, bacillusamides A (1) and B (2), have been isolated from the EtOAc extract of the sea urchin-derived Bacillus sp. along with the known cyclo(-L-pro-L-val-) (3), cyclo(-L-pro-L-tyr-) (4), cyclo(-L-pro-L-phe-) (5). These structures were elucidated by extensive spectroscopic methods. Furthermore, the absolute configurations of the amino acid residues were determined using Marfey's method. Compound 1 displayed weak antifungal activity against Aspergillus niger.
- Yonezawa, Ken,Yamada, Koji,Kouno, Isao
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experimental part
p. 106 - 108
(2011/03/20)
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- NOVEL MULTIMERIC MOLECULES, A PROCESS FOR PREPARING THE SAME AND THE USE THEREOF FOR MANUFACTURING MEDICINAL DRUGS
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The invention relates to a compound of the formula (I): in which k and j are independently 0 or 1, Y is a macrocycle in which the cycle includes 9 to 36 carbon atoms and is functionalised by three amino functions and by a chain for attaching the spacer arm Z via an X bond, Rc is a binding pattern with a receptor of the TNF superfamily, X is a chemical function for binding the Y group to the space arm, and Z is a bi-, tri- or tetra-functional spacer arm.
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- Chiral separation of underivatized amino acids by reactive extraction with palladium-BINAP complexes
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(Figure Presented) In answer to the need for a more economic technology for the separation of racemates, a novel system for reactive enantioselective liquid-liquid extraction (ELLE) is introduced. Palladium (S)-BINAP complexes are employed as hosts in the separation of underivatized amino acids. The system shows the highest selectivity for the ELLE of tryptophan with metal complexes as hosts reported to date and shows a good selectivity toward a range of natural and unnatural amino acids. Furthermore, the host can be prepared in situ from commerically available compounds. Bulk-membrane transport in the form of U-tube experiments demonstrates the enantioselective and catalytic nature of the transport. The dependency of the system on parameters such as pH, organic solvent, and host-substrate ratio has been established. 31P NMR spectroscopy has been used to confirm the preferred enantiomer in the extraction experiments. The intrinsic selectivity was deduced by determination of the association constants of the palladium complex with the tryptophan enantiomers.
- Verkuijl, Bastiaan J. V.,Minnaard, Adriaan J.,De Vries, Johannes G.,Feringa, Ben L.
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experimental part
p. 6526 - 6533
(2010/03/01)
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- An antifungal tetrapeptide from the culture of Penicillium canescens
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A new tetrapeptide D-Phe-L-Val-D-Val-L-Tyr (1), along with three known diketopiperazines and pseurotin A, were isolated from the culture of Penicillium canescens, collected from pollen from beehives, in a screening for new antimicrobial products from unex
- Bertinetti, Brenda V.,Pena, Nora I.,Cabrera, Gabriela M.
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experimental part
p. 1178 - 1184
(2010/04/30)
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- Antineoplastic agents. 570. isolation and structure elucidation of bacillistatins 1 and 2 from a marine bacillus silvestris
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Two new cyclodepsipeptides designated bacillistatins 1 (1)and2(2) have been isolated from cultures of a sample of Bacillus silvestris that was obtained from a Pacific Ocean (southern Chile) crab. Each 12-unit cyclodepsipeptide strongly inhibited growth of a human cancer cell line panel, with GI 50's of 10-4-10-5 μg/mL, and each compound was active against antibiotic-resistant Streptococcus pneumoniae. The structures were elucidated by a combination of X-ray diffraction and mass and 2D NMR spectroscopic analyses, together with chemical degradation.
- Pettit, George R.,Knight, John C.,Herald, Delbert L.,Pettit, Robin K.,Hogan, Fiona,Mukku, Venugopal J. R. V.,Hamblin, John S.,Dodson II, Michael J.,Chapuis, Jean-Charles
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experimental part
p. 366 - 371
(2009/12/25)
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