Identification of a novel gene involved in pilin glycosylation in
The pili of Neisseria meningitidis are a key virulence factor, being major adhesins of this capsulate organism that contribute to specificity for the human host. Recently it has been reported that meningococcal pili are post-translationally modified by the addition of an O-linked trisaccharide, Gal (β1–4) Gal (α1–3) 2,4-diacetimido-2,4,6-trideoxyhexose. Using a set of random genomic sequences from N. meningitidis strain MC58, we have identified a novel gene homologous to a family of glycosyltransferases. A plasmid clone containing the gene was isolated from a genomic library of N. meningitidis strain MC58 and its nucleotide sequence determined. The clone contained a complete copy of the gene, here designated pglA (pilin glycosylation). Insertional mutations were constructed in pglA in a range of meningococcal strains with well-defined lipopolysaccharide (LPS) or pilin-linked glycan structures to determine whether pglA had a role in the biosynthesis of these molecules. There was no alteration in the phenotype of LPS from pglA mutant strains as judged by gel migration and the binding of monoclonal antibodies. In contrast, decreased gel migration of the pilin subunit molecules of pglA mutants was observed, which was similar to the migration of pilins of galE mutants of same strains, supporting the notion that pglA is a glycosyltransferase involved in the biosynthesis of the pilin-linked trisaccharide structure. The pglA mutation, like the galE mutation reported previously, had no effect on pilus-mediated adhesion to human epithelial or endothelial cells. Pilin from pglA mutants were unable to bind to monospecific antisera recognizing the Gal (β1–4) Gal structure, suggesting that PglA is a glycosyltransferase involved in the addition of galactose of the trisaccharide substituent of pilin.
No Supplementary Data
No Article Media
Document Type: Original Article
Department of Microbiology, The University of Queensland, Brisbane, Queensland, 4072, Australia.,
School of Animal and Microbial Sciences, University of Reading, Reading RG6 6AJ, UK.,
National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.,
Molecular Infectious Diseases Group, Department of Paediatrics, University of Oxford, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
August 1, 1998