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Serotype-Converting Bacteriophage SflI Encodes an Acyltransferase Protein That Mediates 6-O-Acetylation of GlcNAc in Shigella flexneri O-Antigens, Conferring on the Host a Novel O-Antigen Epitope.
- Source :
-
Journal of Bacteriology . Oct2014, Vol. 196 Issue 20, p3656-3666. 11p. - Publication Year :
- 2014
-
Abstract
- Shigella flexneri O-antigen is an important and highly variable cell component presented on the outer leaflet of the outer membrane. Most Shigella flexneri bacteria share an O-antigen 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 chemical groups to different sugars, giving rise to diverse O-antigen structures and, correspondingly, to various serotypes. The known modifications include glucosylation on various sugar residues, O-acetylation on RhaI or/and RhaIII, and phosphorylation with phosphoethanolamine on RhaII or/ and RhaIII. Recently, a new O-antigen modification, namely, O-acetylation at position 6 of N-acetylglucosamine (GlcNAc), has been identified in S. flexneri serotypes 2a, 3a, Y, and Yv. In this study, the genetic basis of the 6-O-acetylation of GlcNAc in S. flexneri was elucidated. An O-acyltransferase gene designated oacD was found to be responsible for this modification. The oacD gene is carried on serotype-converting bacteriophage SflI, which is integrated into the host chromosome by lysogeny to form a prophage responsible for the evolvement of serotype 2 of S. flexneri. The OacD-mediated 6-O-acetylation also occurs in some other S. flexneri serotypes that carry a cryptic SflI prophage with a dysfunctional gtr locus for type II glucosylation. The 6-Oacetylation on GlcNAc confers to the host a novel O-antigen epitope, provisionally named O-factor 10. These findings enhance our understanding of the mechanisms of the O-antigen variation and enable further studies to understand the contribution of the O-acetylation to the antigenicity and pathogenicity of S. flexneri. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219193
- Volume :
- 196
- Issue :
- 20
- Database :
- Academic Search Index
- Journal :
- Journal of Bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 98612422
- Full Text :
- https://doi.org/10.1128/JB.02009-14