Wang J, Knirel YA, Lan R, Senchenkova SN, Luo X, Perepelov AV, Wang Y, Shashkov AS, Xu J, Sun Q Identification of an O-acyltransferase gene (oacB) that mediates 3- and 4-O-acetylation of rhamnose III in Shigella flexneri O antigens Journal of Bacteriology196(8) (2014)
1525-1531
NCBI PubMed ID:24509314 Publication DOI:10.1128/JB.01393-13 Journal NLM ID:2985120R Publisher: American Society for Microbiology Correspondence: Jianguo Xu <xujianguoicdc.cn>; Qiangzheng Sun <sunqiangzhengicdc.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.
Found 
report error
icdc.cn>; Qiangzheng Sun <sunqiangzheng