title: O acetylation of the enterobacterial common antigen polysaccharide is catalyzed by the product of the yiaH gene of Escherichia coli K-12.
abstract: The carbohydrate component of the enterobacterial common antigen (ECA) of Escherichia coli K-12 occurs primarily as a water-soluble cyclic polysaccharide located in the periplasm (ECA(CYC)) and as a phosphoglyceride-linked linear polysaccharide located on the cell surface (ECA(PG)). The polysaccharides of both forms are comprised of the amino sugars N-acetyl-D-glucosamine (GlcNAc), N-acetyl-D-mannosaminuronic acid (ManNAcA), and 4-acetamido-4,6-dideoxy-D-galactose (Fuc4NAc). These amino sugars are linked to one another to form trisaccharide repeat units with the structure -->3-alpha-D-Fuc4NAc-(1-->4)-beta-D-ManNAcA-(1-->4)-alpha-D-GlcNAc-(1-->. The hydroxyl group in the 6 position of the GlcNAc residues of both ECA(CYC) and ECA(PG) are nonstoichiometrically esterified with acetyl groups. Random transposon insertion mutagenesis of E. coli K-12 resulted in the generation of a mutant defective in the incorporation of O-acetyl groups into both ECA(CYC) and ECA(PG). This defect was found to be due to an insertion of the transposon into the yiaH locus, a putative gene of unknown function located at 80.26 min on the E. coli chromosomal map. Bioinformatic analyses of the predicted yiaH gene product indicate that it is an integral inner membrane protein that is a member of an acyltransferase family of enzymes found in a wide variety of organisms. The results of biochemical and genetic experiments presented here strongly support the conclusion that yiaH encodes the O-acetyltransferase responsible for the incorporation of O-acetyl groups into both ECA(CYC) and ECA(PG). Accordingly, we propose that this gene be designated wecH.
authors.affiliation: Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799. rickp@usuhs.mil.
authors.forename: Junko
authors.initials: J
authors.lastname: Kajimura
authors.forename: Arifur
authors.initials: A
authors.lastname: Rahman
authors.forename: James
authors.initials: J
authors.lastname: Hsu
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Evans
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Gardner
authors.forename: Paul D
authors.initials: PD
authors.lastname: Rick
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D019295:Computational Biology; D004251:DNA Transposable Elements; D048168:Escherichia coli K12 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016415:Sequence Alignment
chemical_list: D000942:Antigens, Bacterial; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C017286:enterobacterial common antigen; D000123:Acetyltransferases; C515154:YiaH protein, E coli