3-Deoxy-D-manno-octulosonic acid (Kdo) hydrolase identified in Francisella tularensis, Helicobacter pylori, and Legionella pneumophila

J Biol Chem. 2010 Nov 5;285(45):34330-6. doi: 10.1074/jbc.M110.166314. Epub 2010 Aug 26.

Abstract

3-Deoxy-D-manno-octulosonic acid (Kdo) is an eight-carbon sugar ubiquitous in Gram-negative bacterial lipopolysaccharides (LPS). Although its biosynthesis is well described, no protein has yet been identified as a Kdo hydrolase. However, Kdo hydrolase enzymatic activity has been detected in membranes of Helicobacter pylori and Francisella tularensis and may be responsible for the removal of side-chain Kdo from the LPS core saccharides. We now report the identification of genes encoding a Kdo hydrolase in F. tularensis Schu S4 and live vaccine strain strains, in H. pylori 26695 strain and in Legionella pneumophila Philadelphia 1 strain. We have renamed the genes kdhA for keto-deoxyoctulosonate hydrolase A. Deletion of kdhA abolished Kdo hydrolase activity in membranes of F. tularensis live vaccine strain. The F. tularensis kdhA mutant synthesized a core oligosaccharide containing a Kdo disaccharide with one of the Kdo residues being a terminal side chain. This side-chain Kdo monosaccharide was absent in the wild-type core oligosaccharide. Expression in Escherichia coli of recombinant KdhA from F. tularensis, H. pylori, and L. pneumophila resulted in a reduction of membrane-associated side-chain Kdo. The identification of this previously faceless enzyme will accelerate study of the biosynthetic basis and biologic impact for postbiosynthetic LPS structural modification.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacterial Vaccines / genetics
  • Bacterial Vaccines / metabolism
  • Cell Membrane / enzymology
  • Cell Membrane / genetics
  • Francisella tularensis / enzymology*
  • Francisella tularensis / genetics
  • Gene Deletion
  • Glycoside Hydrolases / genetics
  • Glycoside Hydrolases / metabolism*
  • Helicobacter pylori / enzymology*
  • Helicobacter pylori / genetics
  • Legionella pneumophila / enzymology*
  • Legionella pneumophila / genetics
  • Lipopolysaccharides / genetics
  • Lipopolysaccharides / metabolism*
  • Oligosaccharides / genetics
  • Oligosaccharides / metabolism
  • Sugar Acids / metabolism*
  • Vaccines, Attenuated / genetics
  • Vaccines, Attenuated / metabolism

Substances

  • Bacterial Proteins
  • Bacterial Vaccines
  • Lipopolysaccharides
  • Oligosaccharides
  • Sugar Acids
  • Vaccines, Attenuated
  • 2-keto-3-deoxyoctonate
  • Glycoside Hydrolases
  • KDO alpha-octulopyranoside hydrolase