The Haemophilus influenzae HMW1C protein is a glycosyltransferase that transfers hexose residues to asparagine sites in the HMW1 adhesin.

Published

Journal Article

The Haemophilus influenzae HMW1 adhesin is a high-molecular weight protein that is secreted by the bacterial two-partner secretion pathway and mediates adherence to respiratory epithelium, an essential early step in the pathogenesis of H. influenzae disease. In recent work, we discovered that HMW1 is a glycoprotein and undergoes N-linked glycosylation at multiple asparagine residues with simple hexose units rather than N-acetylated hexose units, revealing an unusual N-glycosidic linkage and suggesting a new glycosyltransferase activity. Glycosylation protects HMW1 against premature degradation during the process of secretion and facilitates HMW1 tethering to the bacterial surface, a prerequisite for HMW1-mediated adherence. In the current study, we establish that the enzyme responsible for glycosylation of HMW1 is a protein called HMW1C, which is encoded by the hmw1 gene cluster and shares homology with a group of bacterial proteins that are generally associated with two-partner secretion systems. In addition, we demonstrate that HMW1C is capable of transferring glucose and galactose to HMW1 and is also able to generate hexose-hexose bonds. Our results define a new family of bacterial glycosyltransferases.

Full Text

Cited Authors

  • Grass, S; Lichti, CF; Townsend, RR; Gross, J; St Geme, JW

Published Date

  • May 27, 2010

Published In

Volume / Issue

  • 6 / 5

Start / End Page

  • e1000919 -

PubMed ID

  • 20523900

Pubmed Central ID

  • 20523900

Electronic International Standard Serial Number (EISSN)

  • 1553-7374

International Standard Serial Number (ISSN)

  • 1553-7366

Digital Object Identifier (DOI)

  • 10.1371/journal.ppat.1000919

Language

  • eng