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Xu P, Stevens ED, French AD, Kováč P. Synthesis and molecular structure of the 5-methoxycarbonylpentyl α-glycoside of the upstream, terminal moiety of the O-specific polysaccharide of Vibrio cholerae O1, serotype Inaba. Molecules 2015; 20:2892-902. [PMID: 25679049 PMCID: PMC6272311 DOI: 10.3390/molecules20022892] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/05/2015] [Indexed: 11/16/2022] Open
Abstract
The trimethylsilyl trifluoromethanesulfonate (TMSOTf)-catalyzed reaction of methyl 6-hydroxyhexanoate with 3-O-benzyl-4-(2,4-di-O-acetyl-3-deoxy-l-glycero-tetronamido)-4,6-dideoxy-2-O-levulinoyl-α-d-mannopyranosyl trichloroacetimidate followed by a two-step deprotection (hydrogenolysis over Pd/C catalyst and Zemplén deacylation, to simultaneously remove the acetyl and levulinoyl groups) gave 5-(methoxycarbonyl)pentyl 4-(3-deoxy-l-glycero-tetronamido)-4,6-dideoxy-α-d-mannopyranoside. The structure of the latter, for which crystals were obtained in the analytically pure state for the first time, followed from its NMR and high-resolution mass spectra and was confirmed by X-ray crystallography. The molecule has two approximately linear components; a line through the aglycon intersects a line through the mannosyl and tetronylamido groups at 120°. The crystal packing separates the aglycon groups from the tetronylamido and mannosyl groups, with only C-H…O hydrogen bonding among the aglycon groups and N-H…O, O-H…O and C-H…O links among the tetronylamido and mannosyl groups. A carbonyl oxygen atom accepts the strongest O-H…O hydrogen bond and two strong C-H…O hydrogen bonds. The geometric properties were compared with those of related molecules.
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Affiliation(s)
- Peng Xu
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA.
| | - Edwin D Stevens
- Department of Chemistry, Western Kentucky University, 1906 College Heights Blvd., Bowling Green, KY 42101-1709, USA.
| | - Alfred D French
- Southern Regional Research Center, US Department of Agriculture, 1100 Robert E Lee Blvd, New Orleans, LA 70124, USA.
| | - Pavol Kováč
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA.
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2
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Wade TK, Saksena R, Shiloach J, Kovác P, Wade WF. Immunogenicity of synthetic saccharide fragments of Vibrio cholerae O1 (Ogawa and Inaba) bound to Exotoxin A. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2006; 48:237-51. [PMID: 17010106 DOI: 10.1111/j.1574-695x.2006.00143.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recombinant exotoxin A (rEPA) from Pseudomonas aeruginosa conjugated to Vibrio cholerae O1 serotype-specific polysaccharides (mono-, di- and hexasaccharide) were immunogenic in mice. Monosaccharide conjugates boosted the humoral responses to the hexasaccharide conjugates. Prior exposure to purified Ogawa lipopolysaccharide (LPS) enabled contra-serotype hexasaccharide conjugates to boost the vibriocidal response, but Inaba LPS did not prime for an enhanced vibriocidal response by a contra-serotype conjugate. Prior exposure to the carrier, and priming B cells with the LPS of either serotype, resulted in enhanced vibriocidal titers if the Ogawa hexasaccharides were used, but a diminished response to the Inaba LPS. These studies demonstrate that the 'functional' B cell epitopes on the LPS differ from those of the neoglycoconjugates and that the order of immunization and the serotype of the boosting conjugate can influence the epitope specificity and function of the antisera.
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Affiliation(s)
- Terri K Wade
- Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH 03756, USA.
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3
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Chatterjee SN, Chaudhuri K. Lipopolysaccharides of Vibrio cholerae. I. Physical and chemical characterization. Biochim Biophys Acta Mol Basis Dis 2003; 1639:65-79. [PMID: 14559113 DOI: 10.1016/j.bbadis.2003.08.004] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Vibrio cholerae is the causative organism of the disease cholera. The lipopolysaccharide (LPS) of V. cholerae plays an important role in eliciting the antibacterial immune response of the host and in classifying the vibrios into some 200 or more serogroups. This review presents an account of our up-to-date knowledge of the physical and chemical characteristics of the three constituents, lipid-A, core-polysaccharide (core-PS) and O-antigen polysaccharide (O-PS), of the LPS of V. cholerae of different serogroups including the disease-causing ones, O1 and O139. The structure and occurrence of the capsular polysaccharide (CPS) on V. cholerae O139 have been discussed as a relevant topic. Similarity and dissimilarity between the structures of LPS of different serogroups, and particularly between O22 and O139, have been analysed with a view to learning their role in the causation of the epidemic form of the disease by avoiding the host defence mechanism and in the evolution of the newer pathogenic strains in future. An idea of the emerging trends of research involving the use of immunogens prepared from synthetic oligosaccharides that mimic terminal epitopes of the O-PS of V. cholerae O1 in the development of a conjugate anti cholera vaccine is also discussed.
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Affiliation(s)
- S N Chatterjee
- Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Sector-1, Calcutta-700 064, India.
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4
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Chang AH, Horton D, Kováč P. Syntheses of fluorinated ligands to probe binding of antigenic determinants of Vibrio cholerae O:1, serotypes Inaba and Ogawa, to antibodies. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0957-4166(99)00505-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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González L, Asensio JL, Ariosa-Alvarez A, Vérez-Bencomo V, Jiménez-Barbero J. Solution conformation and dynamics of the trisaccharide fragments of the O-antigen of Vibrio cholerae O1, serotypes Inaba and Ogawa. Carbohydr Res 1999; 321:88-95. [PMID: 10612004 DOI: 10.1016/s0008-6215(99)00167-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The conformational behavior of the trisaccharide fragments of the Ogawa and Inaba Vibrio cholera serotypes has been studied using NMR and molecular dynamics (MD). The obtained results indicate that there are no significant differences in the major conformation and in the extent of motion of the glycosidic torsions of these molecules. The differences in biological activity are probably not due to conformational effects but to van der Waals and/or hydrogen bonding interactions between the antigens and the biological receptor.
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Affiliation(s)
- L González
- Departamento Química Orgánica Biológica, Instituto Química Orgánica, CSIC, Madrid, Spain
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6
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Bystrický S, Szu SC, Zhang J, Kovác P. Conformational differences among mono- and oligosaccharide fragments of O-specific polysaccharides of Vibrio cholerae O1 revealed by circular dichroism. Carbohydr Res 1998; 314:135-9. [PMID: 10230041 DOI: 10.1016/s0008-6215(98)00265-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The circular dichroism (CD) of synthetic mono- and oligosaccharides that represent the terminal, non-reducing group of O-antigens of Vibrio cholerae O1 from the subtypes Ogawa and Inaba was measured in various solvents. We found differences in the CD of the monosaccharides of these subtypes that decrease with increasing chain lengths of the oligosaccharides. The differences can be explained by different orientations of the N-acyl side chain of the terminal monosaccharides. The linear relationship of ellipticity versus the number of residues in an oligosaccharide chain follows the principle of optical superposition. This, together with a similar contribution by internal units to the overall ellipticity, suggests an identical, regular conformation of oligosaccharide fragments of both Ogawa and Inaba series.
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Affiliation(s)
- S Bystrický
- Laboratory of Developmental and Molecular Immunity, NICHD, National Institutes of Health, Bethesda, MD 20892-2720, USA
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7
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Ariosa-Alvarez A, Arencibia-Mohar A, Madrazo-Alonso O, Garcia-Imia L, Sierra-Gonzalez G, Verez-Bencomo V. Synthesis of theVibrio CholeraeO1 Ogawa and Inaba Terminal Disaccharides With Dioxolane-Type Spacers and their Coupling to Proteins1. J Carbohydr Chem 1998. [DOI: 10.1080/07328309808002355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Zhang J, Yergey A, Kowalak J, Kovác P. Studies towards neoglycoconjugates from the monosaccharide determinant of Vibrio cholerae O:1, serotype Ogawa using the diethyl squarate reagent. Carbohydr Res 1998; 313:15-20. [PMID: 9861698 DOI: 10.1016/s0008-6215(98)00261-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of reaction time, concentration and molar excess of hapten upon the efficiency of the conjugation of carbohydrates to proteins using the diethyl squarate reagent has been studied using chicken serum albumin (CSA) as the carrier protein and a linker-equipped D-glucose derivative as the hapten. A high degree of incorporation of the latter into CSA was achieved with high efficiency, and the use of a large excess of the ligand was not necessary. Conjugation of the immunodominant monosaccharide determinant of Vibrio cholerae O:1, serotype Ogawa, bearing the same spacer, followed a similar pattern, showing that the nature of the carbohydrate does not substantially affect the outcome of the conjugation and that a predicted degree of antigen-loading onto carrier protein is possible to achieve.
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Affiliation(s)
- J Zhang
- National Institute of Health: NIDDK, Laboratory of Medicinal Chemistry, Bethesda, MD 20892-0815, USA
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9
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Zhang J, Yergey A, Kowalak J, Kováč P. Linking carbohydrates to proteins using N-(2,2-dimethoxyethyl)-6-hydroxy hexanamide. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)83039-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Zhang J, Kováč P. Synthesis of Some Analogs of the Methyl α-Glycoside of the Presumed Antigenic Determinant of the O-Specific Polysaccharide ofVibrio choleraeO:1, Serotype Ogawa. J Carbohydr Chem 1998. [DOI: 10.1080/07328309808002896] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Zhang J, Kováč P. N-(2,2-dimethoxyethyl)-, N-(2,2-diethoxyethyl)-, and N-(4,4-diethoxybutyl)-6-hydroxy hexanamides as new linking agents for carbohydrates and proteins. Tetrahedron Lett 1998. [DOI: 10.1016/s0040-4039(97)10787-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Ogawa Y, Lei PS, Kovác P. Synthesis of eight glycosides of hexasaccharide fragments representing the terminus of the O-polysaccharide of Vibrio cholerae O:1, serotype Inaba and Ogawa, bearing aglycons suitable for linking to proteins. Carbohydr Res 1996; 293:173-94. [PMID: 8938375 DOI: 10.1016/0008-6215(96)00202-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The title substances were prepared from intermediate, fully acetylated alpha-trimethylsilylethyl (SE) glycosides. The latter were assembled in a blockwise manner, using as the glycosyl donor the alpha-glycosyl chloride of a disaccharide bearing two 4-azido-4-deoxy functions. Next, the azido groups in the assembled hexasaccharides were converted to the corresponding amines, and these were acylated with 4-O-benzyl-3-deoxy-L-glycero-tetronic acid in the presence of a water-soluble carbodiimide. The SE glycosides were then transformed to glycosyl imidates, and these were coupled with methyl 6-hydroxyhexanoate or methyl 2-(2-hydroxyethylthio) propionate. The aglycons in the glycosides thus obtained were then converted to the corresponding carboxylic acids or acyl hydrazides. Such compounds are suitable for linking to proteins to obtain neoglycoproteins.
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Affiliation(s)
- Y Ogawa
- NIDDK, National Institutes of Health, Bethesda, MD 20892-0815, USA
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13
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Lei PS, Ogawa Y, Kováč P. NewN-Acylating Reagents Derived from 3-Deoxy-l-glycero-tetronic Acid1. J Carbohydr Chem 1996. [DOI: 10.1080/07328309608005668] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Lei P, Ogawa Y, Kovác P. Synthesis of the methyl alpha-glycosides of a di-, tri-, and a tetra-saccharide fragment mimicking the terminus of the O-polysaccharide of Vibrio cholerae O:1, serotype Ogawa. Carbohydr Res 1996; 281:47-60. [PMID: 8839176 DOI: 10.1016/0008-6215(95)00331-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Methyl 4-(3-deoxy-L-glycero-tetronamido)-4,6-dideoxy-2-O-methyl-alpha-D- mannopyranoside was acetylated, and the fully protected methyl glycoside was treated with dichloromethyl methyl ether-ZnCl2 (DCMME-ZnCl2) reagent to give 3-O-acetyl-4-(2,4-di-O-acetyl-3- deoxy-L-glycero-tetronamido)-4,6-dideoxy-2-O-methyl-alpha-D-mannop yranosyl chloride (3). Condensation of 3 with methyl 3-O-acetyl-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronamido)-4,6- dideoxy-alpha-D-mannopyranoside (4) gave the fully acetylated disaccharide 5, which was deacetylated yielding the methyl alpha-glycoside of title disaccharide. The disaccharide glycosyl donor required for the blockwise synthesis of the title tri- and the tetra-saccharide, 3-O-acetyl-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronamido)-4,6-d ideoxy-2-O- methyl-alpha-D-mannopyranosyl-(1-->2)-3-O-acetyl-4- (2,4-di-O-acetyl-3-deoxy-L-glycero-tetronamido)-4,6-dideoxy-alpha- D- mannopyranosyl chloride (12), was obtained by condensation of 3 with the 1-O-acetyl analog of 4, followed by treatment of the disaccharide formed with DCMME-ZnCl2. The synthesis of the methyl alpha-glycoside of the title trisaccharide involved a condensation of 12 with 4, followed by deacetylation. Similarly, the condensation of 12 with 15, the latter being the analog of 5 having a free HO-2, followed by deacetylation, gave the methyl alpha-glycoside of the title tetrasaccharide. All glycosylation reactions were mediated by silver trifluoromethanesulfonate in the presence of 2,4,6-trimethylpyridine. 4-(3-Deoxy-L-glycero-tetronamido)-4,6-dideoxy-2-O-methyl-alpha,bet a-D- mannopyranose was prepared for the first time. It was characterized by NMR spectroscopy, and via its crystalline per-O-acetyl derivative. It is the saccharide whose alpha-form constitutes the terminal, non-reducing end-group of the O-PS of V. cholerea O:1, serotype Ogawa.
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Affiliation(s)
- P Lei
- NIDDK, National Institutes of Health, Bethesda, MD 20892-0815, USA
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15
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Lei PS, Ogawa Y, Kovác P. Synthesis of the methyl alpha-glycoside of a trisaccharide mimicking the terminus of the O antigen of Vibrio cholerae O:1, serotype Inaba. Carbohydr Res 1995; 279:117-31. [PMID: 8593618 DOI: 10.1016/0008-6215(95)00281-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Coupling of methyl 4-amino-4,6-dideoxy-2-O-4-methoxybenzyl-alpha-D-mannopyranoside, obtained from the corresponding 4-azido derivative by treatment with H2S, with 3-deoxy-L-glycero-tetronolactone gave the crystalline methyl 4-(3-deoxy-L-glycero-tetronamido)-4,6-dideoxy-2-O-4-methoxybenzyl- alpha-D- mannopyranoside (7). Subsequent acetylation of 7, followed by O-demethoxybenzylation of the 8 formed gave the crystalline methyl 3-O-acetyl-4,6-dideoxy-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetronami do)-alpha- D-mannopyranoside (9), which was used as the key intermediate in the construction of the title trisaccharide. To make a glycosyl donor allowing the extension of the oligosaccharide chain at O-2, compound 9 was converted, via conventional transformations, into 3-O-acetyl-2-O-bromoacetyl-4,6-dideoxy-4-(2,4-di-O-acetyl-3-deoxy-L-glyc ero- tetronamido)-alpha-D-mannopyranosyl chloride (12). Condensation of 12 with 9 afforded the disaccharide 20 having a selectively removable protecting group at O-2(2). The latter was O-debromoacetylated, and the disaccharide nucleophile thus obtained was treated with 2,3-di-O-acetyl-4,6-dideoxy-4-(2,4-di-O-acetyl-3-deoxy-L-glycero-tetr onamido)- alpha-D-mannopyranosyl chloride to give, after O-deacetylation, the target, title trisaccharide. The constituent monosaccharide of the O-specific polysaccharide antigen of Vibrio cholerae serotype Inaba, 4-(3-deoxy-L-glycero-tetronamido)-4,6-dideoxy-D-mannopyranose (18), was obtained from the peracetate of its methyl alpha-glycoside by acetolysis, followed by O-deacetylation. The amorphous compound 18 was characterized by 1H and 13C NMR spectroscopy and through its crystalline alpha-per-O-acetyl derivative.
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Affiliation(s)
- P S Lei
- NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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16
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Ogawa Y, Lei PS, Kovác P. Synthesis of the 2-deoxy analogue of the methyl alpha-glycoside of the monosaccharide repeating unit of the O-polysaccharide of Vibrio cholerae O:1. Carbohydr Res 1995; 277:327-31. [PMID: 8556740 DOI: 10.1016/0008-6215(95)00213-d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Y Ogawa
- NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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17
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Ogawa Y, Lei PS, Kováč P. Synthesis of a functionalized hexasaccharide precursor of a glycoconjugate vaccine against cholera. Bioorg Med Chem Lett 1995. [DOI: 10.1016/0960-894x(95)00397-c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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Lei PS, Ogawa Y, Flippen-Anderson JL, Kovác P. Synthesis and crystal structure of methyl 4-6-dideoxy-4-(3-deoxy-L- glycero-tetronamido)-2-O-methyl-alpha-D-mannopyranoside, the methyl alpha-glycoside of the terminal unit, and presumed antigenic determinant, of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Ogawa. Carbohydr Res 1995; 275:117-29. [PMID: 7585718 DOI: 10.1016/0008-6215(95)00147-l] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Methyl 4-azido-4,6-dideoxy-3-O-benzyl-alpha-D-mannopyranoside and its analogous 3-O-(4-methoxybenzyl) derivative were methylated and the 2-O-methyl derivatives formed were converted into methyl 4-amino-4,6-dideoxy-2-O-methyl-alpha-D- mannopyranoside [sequence: see text]. Reaction of the latter with 3-deoxy-L-glycero-tetronolactone gave the methyl glycoside of 4,6-dideoxy-4-(3-deoxy-L-glycero- tetronamido)-2-methyl-alpha-D-mannopyranose [sequence: see text], the monosaccharide that is reported to be the terminal moiety of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Ogawa. The unit cell packing of the compound, which crystallized as a monohydrate, differs from that of the previously described crystalline compound lacking the 2-O-methyl group. The unmethylated sugar is the terminal moiety of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Inaba. The crystal structure of methyl 4,6-dideoxy-2-O- methyl-4-trifluoroacetamido-alpha-D-mannopyranoside [sequence: see text] is also described.
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Affiliation(s)
- P S Lei
- NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Bystrický S, Szu SC, Gotoh M, Kovác P. Circular dichroism of the O-specific polysaccharide of Vibrio cholerae O1 and some related derivatives. Carbohydr Res 1995; 270:115-22. [PMID: 7585695 DOI: 10.1016/0008-6215(95)00017-n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The O-specific polysaccharide (O-SP) of Vibrio cholerae O1 is a homopolymer of alpha-(1 --> 2)-linked 4-amino-4, 6-dideoxy-D-mannopyranose whose amino group is acylated with 3-deoxy-L-glycero-tetronic acid [N-(3-deoxy-L-glycero- tetronyl)-alpha-D-perosamine]. The circular dichroism (CD) of the O-SP as well as of a number of N-acyl (formyl, acetyl, 4-hydroxybutyl, 3-deoxy-L-and D-glycero-tetronyl) derivatives of methyl alpha-glycosides of 4-amino-4,6-dideoxy-D-mannopyranose (methyl alpha-D-perosaminide) has been studied for solutions in water, acetonitrile and 1,1,1-trifluoroethanol. The strong solvent dependence of the sign and intensity of the CD observed for the monosaccharide amides bearing achiral acyl groups is explained by solvent-mediated change of the orientation of the amido group relative to the proximal hydroxyl group at C-3. A change in the population of the nonplanar conformers with a pyramidal arrangement of bonds at the amido nitrogen has also been considered. The effect of solvents upon the CD spectra of compounds bearing chiral N-acyl substituents is less pronounced than that of their counterparts bearing achiral N-acyl substituents. The sign of the CD for the O-SP was found negative in all solvents used. This result is in agreement with the negative sign of the CD of the n --> pi electron transition observed, independent of the solvent, for the monosaccharide derivative containing the L-glycero-3-deoxytetronamido group, and the positive sign found for its D-glycero-counterpart.
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Affiliation(s)
- S Bystrický
- NICHD, Laboratory of Developmental and Molecular Immunity, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Gotoh M, Kovác P. Synthesis of specifically deoxygenated analogues of the methyl alpha-glycoside of the intracatenary monosaccharide repeating unit of the O-polysaccharide of Vibrio cholerae O:1. Carbohydr Res 1995; 268:73-84. [PMID: 7537627 DOI: 10.1016/0008-6215(94)00319-b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Treatment of methyl alpha-D-perosaminide (1) with gamma-butyrolactone gave the 2'-deoxy analogue of methyl 4,6-dideoxy-4-(3-deoxy-L-glycero-tetronamido)-alpha-D-mannopyranos ide (13), the methyl alpha-glycoside of the intracatenary monosaccharide repeating unit of the O-polysaccharide of Vibrio cholerae O:1. The analogous 4'-deoxy derivative was obtained by hydrogenolysis of a 4'-chlorodeoxy precursor, obtained by chlorination of methyl 2,3-di-O-benzyl-4-(2-O-benzyl-3-deoxy-L-glycero-tetronamido)-4,6-d ideoxy-alpha- D-mannopyranoside with methanesulfonyl chloride in DMF. To obtain the 3-deoxy analogue of 13, methyl 4-amino-2-O-benzyl-4,6-dideoxy-3-O-p-methoxy-benzyl-alpha-D-mannopyranos ide was converted into methyl 2-O-benzyl-4,6-dideoxy-4-(2,4-di-O-benzyl-3-deoxy-L-glycero-tetronami do)- alpha-D-mannopyranoside, which was deoxygenated via the corresponding 3-O-(imidazol-1-ylthiocarbonyl) derivative. Subsequent catalytic debenzylation gave the deoxy compound (24). In an alternative synthesis, which is also generally useful for the preparation of 4-N-acyl-3-deoxy derivatives of 1, methyl 4-azido-4,6-dideoxy-alpha-D-mannopyranoside was converted through a series of transformations into methyl 4-amino-2-O-benzyl-3,4,6-tri-deoxy-alpha-D-mannopyranoside. Subsequent reaction with 2-O-benzyl-3-deoxy-L-glycero-tetronolactone, followed by hydrogenolysis of the formed tetronamido derivative, gave 24.
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Affiliation(s)
- M Gotoh
- NIDDK, National Institutes of Health, Section on Carbohydrates, Bethesda, MD 20892-0815
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21
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Gotoh M, Kováč P. Synthesis of the Methyl α-Glycoside of the Intracatenary Disaccharide Repeating Unit of the O-Polysaccharide ofVibrio CholeraeO:1. A Comparison of two Assembly Strategies. J Carbohydr Chem 1994. [DOI: 10.1080/07328309408011859] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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