Characterization of the recombinant Candida albicans β-1,2-mannosyltransferase that initiates the β-mannosylation of cell wall phosphopeptidomannan

Biochem J. 2014 Jan 15;457(2):347-60. doi: 10.1042/BJ20131012.

Abstract

The presence of β-mannosides in their cell walls confers specific features on the pathogenic yeasts Candida albicans and Candida glabrata compared with non-pathogenic yeasts. In the present study, we investigated the enzymatic properties of Bmt1 (β-mannosyltransferase 1), a member of the recently identified β-mannosyltransferase family, from C. albicans. A recombinant soluble enzyme lacking the N-terminal region was expressed as a secreted protein from the methylotrophic yeast Pichia pastoris. In parallel, functionalized natural oligosaccharides isolated from Saccharomyces cerevisiae and a C. albicans mutant strain, as well as synthetic α-oligomannosides, were prepared and used as potential acceptor substrates. Bmt1p preferentially utilizes substrates containing linear chains of α-1,2-linked mannotriose or mannotetraose. The recombinant enzyme consecuti-vely transfers two mannosyl units on to these acceptors, leading to the production of α-mannosidase-resistant oligomannosides. NMR experiments further confirmed the presence of a terminal βMan (β-1,2-linked mannose) unit in the first enzyme product. In the future, a better understanding of specific β-1,2-mannosyltransferase molecular requirements will help the design of new potential antifungal drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Candida albicans / enzymology*
  • Candida albicans / genetics
  • Cell Wall / enzymology*
  • Mannans / chemistry*
  • Mannans / genetics
  • Mannans / metabolism
  • Mannose / chemistry
  • Mannose / genetics
  • Mannose / metabolism
  • Mannosyltransferases / chemistry*
  • Mannosyltransferases / genetics
  • Mannosyltransferases / metabolism
  • Phosphopeptides / chemistry*
  • Phosphopeptides / genetics
  • Phosphopeptides / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism

Substances

  • Mannans
  • Phosphopeptides
  • Recombinant Proteins
  • phosphopeptidomannan
  • Mannosyltransferases
  • beta-1,2-mannosyltransferase IV
  • Mannose