Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Host organism: Homo sapiens
Associated disease: bacillary dysentery (shigellosis) [ICD11:
1A02 
, ICD11:
SA56 , ICD11:
XN7HG ];
infection due to Shigella flexneri [ICD11:
XN7Y2 ]
NCBI PubMed ID: 24509314Publication DOI: 10.1128/JB.01393-13Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Correspondence: Jianguo Xu <xujianguo
icdc.cn>; Qiangzheng Sun <sunqiangzheng
icdc.cn>
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
O antigen (O polysaccharide) is an important and highly variable cell component present on the surface of cells which defines the serospecificity of Gram-negative bacteria. Most O antigens of Shigella flexneri, a cause of shigellosis, share a backbone composed of →2)-α-L-RhapIII-(1→2)-α-L-RhapII-(1→3)-α-L-RhapI-(1→3)-β-D-GlcpNAc-(1→ repeats, which can be modified by adding various substituents, giving rise to 19 serotypes. The known modifications include glucosylation on various sugar residues, O-acetylation on RhaI, and phosphorylation with phosphoethanolamine on RhaII or/and RhaIII. Recently, two new O-antigen modifications, namely, O-acetylation at position 3 or 4 of RhaIII and position 6 of GlcNAc, have been identified in several S. flexneri serotypes. In this work, the genetic basis for the 3/4-O-acetylation on RhaIII was elucidated. Bioinformatic analysis of the genome of S. flexneri serotype 2a strain Sf301, which carries 3/4-O-acetylation on RhaIII, revealed an O-acyltransferase gene designated oacB. Genetic studies combined with O-antigen structure analysis demonstrated that this gene is responsible for the 3/4-O-acetylation in serotypes 1a, 1b, 2a, 5a, and Y but not serotype 6, which has a different O-antigen backbone structure. The oacB gene is carried by a transposon-like structure located in the proA-adrA region on the chromosome, which represents a novel mechanism of mobilization of O-antigen modification factors in S. flexneri. These findings enhance our knowledge of S. flexneri O-antigen modifications and shed light on the origin of new O-antigen variants.
structure, serotype, O-antigen, Shigella flexneri, gene cluster, rhamnose
Structure type: polymer chemical repeating unit
Location inside paper: p.1525, table S1
Compound class: O-polysaccharide, O-antigen, Shigella serogroup Y antigen, rhamnoglucan
Contained glycoepitopes: IEDB_125613,IEDB_125614,IEDB_127514,IEDB_133752,IEDB_133753,IEDB_133754,IEDB_135813,IEDB_135849,IEDB_136105,IEDB_137340,IEDB_141807,IEDB_141815,IEDB_141816,IEDB_143253,IEDB_151531,IEDB_153213,IEDB_225177,IEDB_885823
Methods: 13C NMR, 1H NMR, NMR-2D, PCR, DNA techniques, de-O-acetylation, genetic methods, bioinformatic analysis, serotyping analysis
Comments, role: O-antigen backbone
Related record ID(s): 30527, 30528, 30529, 30530, 30531, 30532, 30533, 30534, 30535, 30536, 30537, 30538, 30539, 30540, 30541, 30542, 30543, 30544, 30545, 30546, 30547
NCBI Taxonomy refs (TaxIDs): 623,
424720Reference(s) to other database(s): GTC:G98477AV, GlycomeDB:
3543, CCSD:
2501, CBank-STR:8288, GenDB:AFl28887
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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