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Mukherjee MM, Xu P, Stevens ED, Kováč P. Towards the Complete Synthetic O-Antigen of Vibrio cholerae O1, Serotype Inaba: Improved Synthesis of the Conjugation-ready Upstream Terminal Hexasaccharide Determinant. RSC Adv 2019; 9:36440-36454. [PMID: 33791092 PMCID: PMC8009174 DOI: 10.1039/c9ra08232h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Synthesis of the upstream terminal hexasaccharide part of the lipopolysaccharides (LPS) of Vibrio cholerae O1, serotype Inaba has been improved. The key improvements include but are not limited to optimized conditions for the stereoselectivity of glycosylation reactions involved and fewer number of synthetic steps, compared to previous approaches. Particularly noteworthy is conducting the glycosylation of the very reactive glycosyl acceptor 8-azido-3,6-dioxaoctanol with the fully assembled hexasaccharide trichloroacetimidate under thermodynamic control. It produced the desired α glycoside with an α : β ratio of 7 : 1, compared with the ratio of 1.1 : 1, observed when the coupling was conducted conventionally. Several substances, which were previously obtained in purity acceptable only for synthetic intermediates, were now obtained in the analytically pure state and were fully characterized. The structure of the key trisaccharide glycosyl acceptor was confirmed by single-crystal X-ray structure determination. Improved synthesis of the conjugation-ready upstream terminal hexasaccharide determinant has been described with special reference to the stereoselectivity refinement.![]()
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Affiliation(s)
| | - Peng Xu
- LBC, NIDDK, National Institutes of Health, Bethesda, MD 20892-0815
| | - Edwin D Stevens
- Department of Chemistry, Western Kentucky University, Bowling Green, KY, 42101
| | - Pavol Kováč
- LBC, NIDDK, National Institutes of Health, Bethesda, MD 20892-0815
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Hou SJ, Kováč P. Enhanced stereoselectivity of alpha-mannosylation under thermodynamic control using trichloroacetimidates. Carbohydr Res 2010; 345:999-1007. [PMID: 20381793 PMCID: PMC2902152 DOI: 10.1016/j.carres.2010.03.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/17/2010] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
O-Specific polysaccharides of Vibrio cholerae O1, serotypes Inaba and Ogawa, consist of alpha-(1-->2)-linked N-(3-deoxy-L-glycero-tetronyl)perosamine (4-amino-4,6-dideoxy-D-mannose). The blockwise synthesis of larger fragments of such O-PSs involves oligosaccharide glycosyl donors that contain a nonparticipating 2-O-glycosyl group at the position vicinal to the anomeric center where the new glycosidic linkage is formed. Such glycosyl donors may bear at C-4 either a latent acylamino (e.g., azido) or the 3-deoxy-L-glycero-tetronamido group. While monosaccharide glycosyl donors, even those bearing a nonparticipating group at O-2 (e.g., methyl), and the 4-N-(3-deoxy-L-glycero-tetronyl) side chain form alpha-linked oligosaccharides with excellent stereoselectivity, alpha-mannosylation with analogous oligosaccharide donors in this series is adversely affected by the presence of the side chain. Consequently, the unwanted beta-product is formed in a considerable amount. Conducting the reaction at elevated temperature under thermodynamic control substantially enhances formation of the alpha-linked oligosaccharide. This effect is much more pronounced when glycosyl trichloroacetimidates, rather than thioglycosides or glycosyl chlorides, are used as glycosyl donors.
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Affiliation(s)
- Shu-jie Hou
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815 (U.S.A.)
| | - Pavol Kováč
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815 (U.S.A.)
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Abronina PI, Galkin KI, Backinowsky LV, Grachev AA. Synthesis of a derivative of a pentasaccharide repeating unit of the O-antigenic polysaccharide of the bacterium Klebsiella pneumoniae O3 as a benzoylated 2-methoxycarbonylethyl thioglycoside. Russ Chem Bull 2010. [DOI: 10.1007/s11172-010-0033-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Saksena R, Chernyak A, Kovác P. Synthesis of spacer-equipped di-, tri-, and the tetrasaccharide fragments of the deacetylated O-PS1 of Citrobacter gillenii O9a,9b, and a related pentasaccharide. Carbohydr Res 2008; 343:1693-706. [PMID: 18436197 DOI: 10.1016/j.carres.2008.03.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 03/20/2008] [Accepted: 03/30/2008] [Indexed: 10/22/2022]
Abstract
The title rhamnooligosaccharides [alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-1-O-(CH(2))(5)COOMe, alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-1-O-(CH(2))(5)COOMe, alpha-D-Rhap4NAc-(1-->2)-alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-1-O-(CH(2))(5)COOMe, and alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-(1-->2)-alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-(1-->3)-alpha-D-Rhap4NAc-1-O-(CH(2))(5)COOMe] were synthesized in a stepwise fashion from 5-methoxycarbonylpentyl 4-azido-4,6-dideoxy-2-O-benzyl-alpha-D-mannopyranoside and orthogonally protected 1-thioglycoside glycosyl donors. The amorphous, final products were fully characterized as corresponding per-O-acetyl derivatives.
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Affiliation(s)
- Rina Saksena
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA
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Saksena R, Chernyak A, Karavanov A, Kovác P. Conjugating low molecular mass carbohydrates to proteins. 1. Monitoring the progress of conjugation. Methods Enzymol 2003; 362:125-39. [PMID: 12968361 DOI: 10.1016/s0076-6879(03)01010-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- Rina Saksena
- Laboratory of Medicinal Chemistry, Section on Carbohydrates, National Institutes of Health, NIDDK, 8 Center Drive, Building 8, Bethesda, Maryland 20892, USA
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Saksena R, Chernyak A, Poirot E, Kovác P. Conjugating low molecular mass carbohydrates to proteins. 2. Recovery of excess ligand used in the conjugation reaction. Methods Enzymol 2003; 362:140-59. [PMID: 12968362 DOI: 10.1016/s0076-6879(03)01011-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- Rina Saksena
- Laboratory of Medicinal Chemistry, Section on Carbohydrates, National Institutes of Health, NIDDK, 8 Center Drive, Building 8, Bethesda, Maryland 20892, USA
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Saksena R, Ma X, Kovác P. One-pot preparation of a series of glycoconjugates with predetermined antigen–carrier ratio from oligosaccharides that mimic the O-PS of Vibrio cholerae O:1, serotype Ogawa. Carbohydr Res 2003; 338:2591-603. [PMID: 14670719 DOI: 10.1016/s0008-6215(03)00273-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Di-through the pentasaccharide that mimic the upstream terminus of the O-specific polysaccharide of Vibrio cholerae O:1, serotype Ogawa were synthesized in the form of 5-methoxycarbonylpentyl glycosides and linked to BSA using squaric acid diester chemistry. The conjugation reactions were monitored by surface-enhanced laser-desorption/ionization-time-of-flight mass spectrometry (SELDI-TOF MS), which allowed conducting the conjugation of the synthetic oligosaccharides in a controlled way and termination of the reaction when the desired molar hapten-BSA ratio had been reached. This made it possible to prepare, from one hapten in a one-pot reaction, a series of neoglycoconjugates having different, predetermined carbohydrate-carrier ratios. The accuracy of molecular mass determination in SELDI-TOF MS analysis could be increased by using the carrier protein as the internal standard.
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Affiliation(s)
- Rina Saksena
- Laboratory of Medicinal Chemistry, National Institute Diabets and Digestive and Kidney Diseases, National Institutes of Health, Building 8, Rm B1A24, Bethesda, MD 20892-0815, USA
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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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Ogawa Y, Kovac P. Synthesis of the dodecasaccharide fragment representing the O-polysaccharide of Vibrio cholerae O:1, serotype Ogawa, bearing an aglycon offering flexibility for chemical linking to proteins. Glycoconj J 1997; 14:433-8. [PMID: 9249140 DOI: 10.1023/a:1018591132723] [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: 02/05/2023]
Abstract
Two azidohexasaccharide building blocks, of which the glycosyl acceptor was the 5-(methoxycarbonyl)pentyl glycoside, were coupled using the trichloroacetimidate technology. The 12 azido functions present in the dodecasaccharide thus formed were then converted to amino groups using hydrogen sulfide as a reducing reagent. Subsequent N-acylation with 4-O-benzyl-L-glycero-tetronic acid, followed by catalytic debenzylation yielded the desired spacer-equipped, title dodecasaccharide.
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Affiliation(s)
- Y Ogawa
- NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0815, USA
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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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