| 1. |
|
|
| 2. |
|
|
| 3. |
- Nazarenko, E. L., et al.
(författare)
-
Structure of the O-specific polysaccharide from Shewanella japonica KMM 3601 containing 5,7-diacetamido-3,5,7,9-tetradeoxy-ᴅ-glycero-ᴅ-talo-non-2-ulosonic acid
- 2011
-
Ingår i: Biochemistry (Moscow). - 0006-2979 .- 1608-3040. ; 76:7, s. 791-796
-
Tidskriftsartikel (refereegranskat)abstract
- Structure of the O-specific polysaccharide chain of the lipopolysaccharide (LPS) of Shewanella japonica KMM 3601 was elucidated. The initial and O-deacylated LPS as well as a trisaccharide representing the O-deacetylated repeating unit of the O-specific polysaccharide were studied by sugar analysis along with 1H and 13C NMR spectroscopy. The polysaccharide was found to contain a rare higher sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-ᴅ-glycero-ᴅ-talo-non-2-ulosonic acid (a derivative of 4-epilegionaminic acid, 4eLeg). The following structure of the trisaccharide repeating unit was established: →4)-α-4eLegp5Ac7Ac-(2→4)-β-ᴅ-GlcpA3Ac-(1→3)-β-ᴅ-GalpNAc-(1→.
|
|
| 4. |
|
|
| 5. |
- Liu, Bin, et al.
(författare)
-
Genetic and structural relationships of Salmonella O55 and Escherichia coli O103 O-antigens and identification of a 3-hydroxybutanoyltransferase gene involved in the synthesis of a Fuc3N derivative
- 2010
-
Ingår i: Glycobiology. - : Oxford University Press. - 0959-6658 .- 1460-2423. ; 20:6, s. 679-688
-
Tidskriftsartikel (refereegranskat)abstract
- O-antigen (O-polysaccharide), a part of the outer membrane of Gram-negative bacteria, is one of the most variable cell constituents and is related to bacterial virulence. O-antigen diversity is almost entirely due to genetic variations in O-antigen gene clusters. In this study, the O-polysaccharide structures of Salmonella O55 and Escherichia coli O103 were elucidated by chemical analysis and nuclear magnetic resonance spectroscopy. It was found that the O-polysaccharides have similar pentasaccharide O-units, which differ only in one sugar (glucose versus N-acetylglucosamine) and in the N-acyl group (acetyl versus 3-hydroxybutanoyl) on 3-amino-3,6-dideoxy-d-galactose (d-Fuc3N). The Salmonella O55 antigen gene cluster was sequenced and compared with the E. coli O103 antigen gene cluster reported previously. The two gene clusters were found to share high-level similarity (DNA identity ranges from 53% to 76%), except for two putative acyl transferase genes (fdtC in Salmonella O55 and fdhC in E. coli O103) which show no similarity. Replacement of the fdtC gene in Salmonella O55 with the fdhC gene from E. coli O103 resulted in production of a modified O-antigen, which contains a 3-hydroxybutanoyl derivative of Fuc3N in place of 3-acetamido-3,6-dideoxygalactose. This finding strongly suggests that fdhC is a 3-hydroxybutanoyltransferase gene. The sequence similarity level suggested that the O-antigen gene clusters of Salmonella O55 and E. coli O103 originate from a common ancestor, and this evolutionary relationship is discussed.
|
|
| 6. |
- Liu, Bin, et al.
(författare)
-
Structure and genetics of Escherichia coli O antigens
- 2020
-
Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 44:6, s. 655-683
-
Forskningsöversikt (refereegranskat)abstract
- Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and three (O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Perepelov, Andrei V., et al.
(författare)
-
Structure and genetics of the O-antigen of Escherichia coli O169 related to the O-antigen of Shigella boydii type 6
- 2015
-
Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 414, s. 46-50
-
Tidskriftsartikel (refereegranskat)abstract
- The O-polysaccharide (O-antigen) of Escherichia coli O169 was studied by sugar analysis along with 1D and 2D H-1 and C-13 NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established: [GRAPHICS] The O-polysaccharide of E. coli O169 differs from that of Shigella boydii type 6 only in the presence of a side-chain glucose residue. A comparison of the O-antigen biosynthesis gene clusters between the galF to gnd genes in the genomes of the two bacteria revealed their close relationship. The glycosyltransferase gene responsible for the formation of the beta-D-Glcp-(1 -> 6)-alpha-D-Galp linkage in the O-antigen was identified in the gene cluster.
|
|
| 10. |
- Perepelov, Andrei V., et al.
(författare)
-
Structures and gene clusters of the closely related O-antigens of Escherichia coli O46 and O134, both containing D-glucuronoyl-D-allothreonine
- 2015
-
Ingår i: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 409, s. 20-24
-
Tidskriftsartikel (refereegranskat)abstract
- The O-polysaccharides (O-antigens) were isolated by mild acid degradation of the lipopolysaccharide (LPS) of Escherichia coli O46 and O134. The structures of their linear tetrasaccharide repeating units were established by sugar analysis along with 1D and 2D H-1 and C-13 NMR spectroscopy: [GRAPHICS] where D-aThr indicates D-allothreonine and R indicates O-acetyl substitution (similar to 70% on aThr and similar to 15% on GalNAc) in E. coli O46 whereas the O-acetylation is absent in E. coli O134. Functions of genes in the essentially identical O-antigen gene clusters of E. coli O46 and O134 were tentatively assigned by a comparison with sequences in available databases and found to be in agreement with the O-polysaccharide structures established.
|
|
