title: Molecular 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.
abstract: 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.
authors.affiliation: Department of Microbiology, University of Illinois, Urbana 61801, USA. j-slauch@uiuc.edu
authors.forename: J M
authors.initials: JM
authors.lastname: Slauch
authors.forename: A A
authors.initials: AA
authors.lastname: Lee
authors.forename: M J
authors.initials: MJ
authors.lastname: Mahan
authors.forename: J J
authors.initials: JJ
authors.lastname: Mekalanos
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D019081:O Antigens / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D012486:Salmonella typhimurium / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D019081:O Antigens; D011994:Recombinant Proteins; D000217:Acyltransferases; D000123:Acetyltransferases; C101959:OafA protein, Salmonella typhimurium