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References to other databases: GTC:G31519FO, GlycomeDB:27606
Structural formula & atomic coordinates
Sweet-II 3D model
Show glycosyltransferases

The structure of the O-antigenic polysaccharide (PS) from the enteroaggregative Escherichia coli strain 522/C1 has been determined. Component analysis and (1)H and (13)C NMR spectroscopy techniques were used to elucidate the structure. Inter-residue correlations were determined by (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation experiments. The PS is composed of pentasaccharide repeating units with the following structure: Analysis of NMR data reveals that on average the PS consists of four repeating units and indicates that the biological repeating unit contains an N-acetylgalactosamine residue at its reducing end. Serotyping of the E. coli strain 522/C1 showed it to be E. coli O178:H7. Determination of the structure of the O-antigen PS of the international type strain from E. coli O178:H7 showed that the two polysaccharides have identical repeating units. In addition, this pentasaccharide repeating unit is identical to that of the capsular polysaccharide from E. coli O9:K38, which also contains O-acetyl groups

NMR, structure, chemistry, clinical, correlation, strain, structural, capsular, polysaccharide, O-antigen, repeating unit, analysis, O antigen, group, Escherichia, Escherichia coli, determination, O-antigenic, O-antigenic polysaccharide, capsular polysaccharide, type, NMR spectroscopy, biological, polysaccharides, medicine, spectroscopy, structural studies, pentasaccharide, component, N-acetylgalactosamine, reducing, reducing end, serotyping, PDF, organic, bacteriology, O-acetyl, biological repeating unit, Enteroaggregative

NCBI PubMed ID: 16005446
Journal NLM ID: 0043535
Publisher: Elsevier
Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden, Department of Laboratory Medicine, Division of Clinical Bacteriology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden, Department of Chemistry and Physiological Sciences, Universidad Nacional Autonoma de Nicaragua, UNAN-Leon, Nicaragua
Methods: NMR-2D, NMR, composition analysis

Capsular polysaccharides (CPSs), or K-antigens, are the major surface antigens of Escherichia coli. More than 80 serologically unique K-antigens are classified into four groups (Groups 1-4) of capsules. Group 1 and 4 contain the Wzy-dependent polymerization pathway and the gene clusters are in the order galF to gnd; Group 2 and 3 contain the ABC transporter-dependent pathway and the gene clusters consist of three regions, region 1, 2 and 3. Little is known about the variations among the gene clusters. In this study, nine serotypes of K-antigen gene clusters (K2ab, K11, K20, K24, K38, K84, K92, K96, and K102), were sequenced and correlated with their CPS chemical structures. Based on the sequence data, a K-antigen specific suspension array that detects 10 distinct CPSs, including the above nine CPSs plus K30, was developed. This is the first report to catalog the genetic features of E. coli K-antigen variations, and to develop a suspension array for their molecular typing. The method has a number of advantages over traditional bacteriophage and serum agglutination methods, and lays the foundation for straightforward identification and detection of additional K-antigens in the future.

antigen, K-antigen, gene cluster, identification, biotechnology, E.coli, suspension array, biological sciences

NCBI PubMed ID: 29357266
Publication DOI: 10.1139/cjm-2017-0620
Journal NLM ID: 0372707
Publisher: National Research Council of Canada
Correspondence: Boyang Cao ; Lei Wang
Institutions: Nankai University, 12538, TEDA Institute of Biological Sciences and Biotechnology, Tianjin, China
Methods: PCR, DNA sequencing, genetic methods, function analysis of gene clusters

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 four (O14, 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.

structure, O antigen, Escherichia coli, gene cluster, serogroup, diversity

NCBI PubMed ID: 31778182
Publication DOI: 10.1093/femsre/fuz028
Journal NLM ID: 8902526
Publisher: Oxford University Press
Correspondence: G. Widmalm ; Lei Wang
Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin, China, The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, China, School of Molecular and Microbial Bioscience (G08), University of Sydney, Sydney, Australia, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China