Premium
Molecular and chemical characterization of the lipopolysaccharide O‐antigen and its role in the virulence of Yersinia enterocolitica serotype O:8
Author(s) -
Zhang Lijuan,
RadziejewskaLebrecht Joanna,
KrajewskaPietrasik Danuta,
Toivanen Paavo,
Skurnik Mikael
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.1871558.x
Subject(s) - biology , gene cluster , complementation , gene , orfs , operon , transferase , nucleic acid sequence , mutant , genetics , microbiology and biotechnology , open reading frame , biochemistry , peptide sequence , enzyme
The Y. enterocolitica O:8 (YeO8) O‐antigen repeat units consist of five sugar residues: N‐acetyl‐ d ‐galactosamine (GalNAc), d ‐galactose (Gal), d ‐mannose (Man), l ‐fucose (Fuc), and 6‐deoxy‐ d ‐gulose (6d‐Gul). The nucleotide sequence of the O‐antigen gene cluster of the YeO8 strain 8081‐c was determined. Altogether, 18 open reading frames (ORFs) were identified and shown to be essential for O‐antigen biosynthesis. We previously characterized the 3′‐end of the O‐antigen gene cluster and identified four genes: two for GDP‐Man biosynthesis, one for UDP‐Gal biosynthesis, and one for O‐antigen polymerase. Based on sequence similarity, Tn 5 ‐insertion phenotypes and chemical analysis, the 14 new genes were assigned the following functions: four genes are involved in the biosynthesis of CDP‐6d‐Gul and two in GDP‐Fuc biosynthesis. Five gene products were assigned sugar transferase functions and one gene product was similar to Wzx, the O‐antigen flippase. Two genes remained unassigned. By genetic complementation we also showed that YeO8 O‐antigen biosynthesis was dependent on N‐acetyl‐glucosaminyl:undecaprenylphosphate transferase (GlcNAc transferase), the WecA (formerly known as Rfe) protein. Data obtained from chemical‐composition analysis suggest that in addition to being GlcNAc transferase, WecA may also function as a GalNAc transferase. Using a restriction‐deficient derivative of Y. enterocolitica O:8 strain 8081, a rough mutant, designated 8081‐R2, was isolated. 8081‐R2 was complemented in trans with a cloned O‐antigen gene cluster restoring surface O‐antigen expression. The virulence of the wild‐type strain and that of the complemented strain were significantly higher (approx. 100‐fold) than that of the rough mutant in an orally infected mouse model, showing that YeO8 O‐antigen is a virulence factor.