title: Identification of three oligo-/polysaccharide-specific ligases in Yersinia enterocolitica.
abstract: In lipopolysaccharide (LPS) biosynthesis of gram-negative bacteria the lipid A-core oligosaccharide (LA-core) and O-polysaccharide (O-PS) biosynthesis pathways proceed separately and converge in periplasmic space where the waaL-encoded ligase joins O-PS onto LA-core. Enterobacterial common antigen (ECA) biosynthesis follows that of O-PS except that ECA is usually ligated to phosphatidylglycerol (PG) and only rarely to LA-core. In Yersinia enterocolitica serotype O:3 LPS is composed of LA-inner core (IC) onto which a homopolymeric O-PS, a hexasaccharide called outer core (OC), and/or ECA are ligated. We found that an individual O:3 LPS molecule carries either OC or O-PS substitution but not both. Related to this, we identified three genes in Y. enterocolitica O:3 that all expressed O-PS ligase activity in the Escherichia coliΔwaaL mutant. The LPS phenotypes of Y. enterocolitica O:3 single, double and triple ligase mutants indicated that two of ligases, named as WaaL(os) and WaaL(ps) , had a preferred substrate specificity for OC and O-PS, respectively, although with some promiscuity between the ligases; the third ligase named as WaaL(xs) was not involved in LPS or ECA biosynthesis. In Y. enterocolitica O:8 the WaaL(os) homologue (Ye1727) ligated a single pentasaccharide O-unit to LA-IC suggesting that in both Y. enterocolitica O:3 and O:8 WaaL(os) is an oligosaccharide (OS)-specific ligase. Finally, Yersinia pestis and Y. pseudotuberculosis carry only the waaL(ps) gene, while either waaL(os) or waaL(xs) or both are additionally present in other Yersinia species. This is the first report on the presence of three different oligo-/polysaccharide-specific ligases in a single bacterium.
authors: Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland.
authors: Elise
authors: E
authors: Pinta
authors: Zhilin
authors: Z
authors: Li
authors: Julia
authors: J
authors: Batzilla
authors: Maria
authors: M
authors: Pajunen
authors: Tiina
authors: T
authors: Kasanen
authors: Kamila
authors: K
authors: Rabsztyn
authors: Alexander
authors: A
authors: Rakin
authors: Mikael
authors: M
authors: Skurnik
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D015008:Yersinia enterocolitica / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides; D008025:Ligases