ABSTRACT
Synthesis of the title trisaccharide was accomplished by sugar chain extension starting from the non-reducing terminus: coupling of Glcp NAc with LD-Hepp, then adding Glcp-OAll. An alternative route started from the reducing end: coupling of LD-Hepp with Glcp-OAll, then addition of Glcp NAc. In the synthesis of the title disaccharide a modification of the first approach was employed. The allyl glycosides were coupled with cysteamine, activated with thiophosgene and conjugated to bovine serum albumin (BSA). The neoglycoconjugates obtained were used in immunochemical studies of monoclonal and polyclonal antibodies directed against Escherichia coli K-12 lipopolysaccharide.
Subject(s)
Disaccharides/analysis , Escherichia coli/chemistry , Heptoses/analysis , Lipopolysaccharides/chemistry , Oligosaccharides/chemistry , Trisaccharides/analysis , Carbohydrate Sequence , Molecular Sequence Data , Oxidation-Reduction , Serologic TestsABSTRACT
The synthesis of the allyl beta-glycosides (8 and 20, respectively) of beta-D-GlcpA-(1----4)-D-Glcp and beta-D-Glcp-(1----3)-D-GlcpA (overlapping disaccharide fragments A and B) in the linear chain of the capsular polysaccharide (S3) from Streptococcus pneumoniae type 3 is described. Oxidation of allyl 2,3,6,2',3',4'-hexa-O-acetyl-beta-cellobioside with chromic acid and saponification of the product gave 8. The synthesis of 20 involved glycosylation of methyl 5-O-acetyl-1,2-O-isopropylidene-alpha-D-glucofuranuronate or its 3-O-trityl derivative and subsequent furanose----pyranose transformation. The derivatives 8 and 20 were each copolymerised with acrylamide. In serological tests (enzyme immunoassay and passive hemagglutination), the resulting antigens exhibited the specificity of S3. It was concluded that fragment A was a much stronger immunodeterminant than fragment B.
Subject(s)
Polysaccharides, Bacterial/chemical synthesis , Streptococcus pneumoniae/immunology , Carbohydrate Conformation , Carbohydrate Sequence , Indicators and Reagents , Magnetic Resonance Spectroscopy , Optical RotationABSTRACT
Oxidation of acetates of allyl and 2-(benzyloxycarbonylamino)ethyl beta-cellobiosides (with OH-4' and OH-6' unprotected) with the Jones reagent followed by esterification (with diazomethane or phenyldiazomethane) gave corresponding uronates with OH-4' unsubstituted. Condensation of these glycosyl acceptors and benzylated derivatives of D-galactose or 4-O-(alpha-D-glucopyranosyl)-D-galactose led to the protected tri- and tetrasaccharide fragments of the capsular polysaccharide from Streptococcus pneumoniae type 8.
Subject(s)
Polysaccharides, Bacterial/chemistry , Streptococcus pneumoniae/metabolism , Carbohydrate Sequence , Esterification , Molecular Sequence Data , Oligosaccharides/chemistryABSTRACT
Di-, tri- and tetrasaccharide fragments of the linear chain of the capsular polysaccharide of Streptococcus pneumoniae type 3 consisting of glucose and glucuronic acid residues connected with beta 1----3- and beta 1----4-glycosidic linkage have been synthesised. A new method for selective deprotection of C3-hydroxyl group in the glucopyranuronic acid moiety is proposed.
Subject(s)
Oligosaccharides/chemical synthesis , Polysaccharides, Bacterial/chemical synthesis , Streptococcus pneumoniae/immunology , Chemical Phenomena , Chemistry , Glycosylation , Oligosaccharides/immunologyABSTRACT
The synthesis of a versatile trisaccharide synthon is described with the combination of protecting groups suitable for preparing higher oligosaccharides of the sequence Man-Rha-Gal and for introducing side-chain substituents (such as residues of 3,6-dideoxy-hexoses and alpha-D-glucose). This synthon was used for the synthesis of protected tri- and hexasaccharide fragments (as 2-phtalimidoethyl glycosides) of Salmonella polysaccharides (serological groups A, B, and D1).
Subject(s)
Oligosaccharides/chemical synthesis , Salmonella/immunology , Thioglycosides , Antigens, Bacterial , Carbohydrate Sequence , Chemical Phenomena , Chemistry , Molecular Sequence Data , O AntigensABSTRACT
The synthesis of allyl beta-glycoside of cellobiuronic acid by chemical modification of cellobiose was described. The carbohydrate-containing polymers with different content of determinant groups were obtained via radical copolymerization of this hapten with acrylamide. The copolymer which contained 27% carbohydrates and had molecular mass about 100-300 kilodaltons had the serological specificity of the capsular polysaccharide Streptococcus pneumoniae type 3 as shown by an enzyme linked immunosorbent assay.
Subject(s)
Polysaccharides, Bacterial/chemical synthesis , Streptococcus pneumoniae/immunology , Chemical Phenomena , Chemistry , Enzyme-Linked Immunosorbent Assay , Polymers , Polysaccharides, Bacterial/analysisABSTRACT
New methods of chemical and chemoenzymatic synthesis of nucleoside 5'-thiophosphates and 5'-alpha-thiotriphosphates are developed. The 5'-alpha-thiotriphosphates are used as substrates both in template-dependent enzymatic PCR synthesis and in a T7-RNA transcription polymerase system. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2003, vol. 29, no. 6; see also http://www.maik.ru.
Subject(s)
DNA-Directed RNA Polymerases/metabolism , Nucleosides/chemical synthesis , Organophosphorus Compounds/chemistry , Sulfhydryl Compounds/chemistry , Base Sequence , Electrophoresis, Agar Gel , Nuclear Magnetic Resonance, Biomolecular , Nucleosides/chemistry , Nucleosides/metabolism , Substrate Specificity , Viral ProteinsABSTRACT
The biotechnological method of synthesis of ribavirin, vidarabin, and 6-azauridine by the use of immobilized recombinant enzymatic preparations of nucleoside phosphorylase was improved. The effect of ribavirin and its combinations with the other synthesized nucleosides on the reproduction of Vaccinia virus was studied using cultures of Vero cells. The combination of ribavirin and vidarabin was shown to provide an antiviral effect at lesser concentrations than when these compounds were taken separately. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.