title: Identification of a distinct, cryptic heparosan synthase from Pasteurella multocida types A, D, and F.
abstract: The extracellular polysaccharide capsules of Pasteurella multocida types A, D, and F are composed of hyaluronan, N-acetylheparosan (heparosan or unsulfated, unepimerized heparin), and unsulfated chondroitin, respectively. Previously, a type D heparosan synthase, a glycosyltransferase that forms the repeating disaccharide heparosan backbone, was identified. Here, a approximately 73% identical gene product that is encoded outside of the capsule biosynthesis locus was also shown to be a functional heparosan synthase. Unlike PmHS1, the PmHS2 enzyme was not stimulated greatly by the addition of an exogenous polymer acceptor and yielded smaller- molecular-weight-product size distributions. Virtually identical hssB genes are found in most type A, D, and F isolates. The occurrence of multiple polysaccharide synthases in a single strain invokes the potential for capsular variation.
authors.affiliation: Dept. of Biochemistry and Molecular Biology, Univ. of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA. paul-deangelis@ouhsc.edu
authors.forename: Paul L
authors.initials: PL
authors.lastname: Deangelis
authors.forename: Carissa L
authors.initials: CL
authors.lastname: White
mesh_terms: D016667:Bacterial Capsules; D001426:Bacterial Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016979:Pasteurella multocida / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D016695:Glycosyltransferases; C450833:heparosan synthase