Open AccessMolecular characterization of the oafA locus responsible for acetylation of Salmonella typhimurium O-antigen: oafA is a member of a family of integral membrane trans-acylases
Author(s) -
James M. Slauch,
Angela A. Lee,
Michael J. Mahan,
John J. Mekalanos
Publication year - 1996
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.178.20.5904-5909.1996
Subject(s) - biology , epitope , salmonella , bacterial outer membrane , antigen , microbiology and biotechnology , locus (genetics) , lipopolysaccharide , bacteria , homology (biology) , gene , open reading frame , peptide sequence , escherichia coli , serotype , genetics , endocrinology
Lipopolysaccharide (LPS) coats the surface of gram-negative bacteria and serves to protect the cell from its environment. The O-antigen is the outermost part of LPS and is highly variable among gram-negative bacteria. Strains of Salmonella are partly distinguished by serotypic differences in their O-antigen. In Salmonella typhimurium, the O-antigen is acetylated, conferring the 05 serotype. We have previously provided evidence that this modification significantly alters the structure of the O-antigen and creates or destroys a series of conformational epitopes. Here we report the detailed mapping, cloning, and DNA sequence of the oafA gene. The locus contains one open reading frame that is predicted to encode an inner membrane protein, consistent with its role in modification of the O-antigen subunit. The OafA protein shows homology to proteins in a number of prokaryotic and one eukaryotic species, and this defines a family of membrane proteins involved in the acylation of exported carbohydrate moieties. In many of these instances, acylation defines serotype or host range and thus has a profound effect on microbe-host interaction.