UDP-(5F)-GlcNAc acts as a slow-binding inhibitor of MshA, a retaining glycosyltransferase

Patrick A. Frantom, James K. Coward, John S. Blanchard

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Glycosyltransferase enzymes play important roles in numerous cellular pathways. Despite their participation in many therapeutically relevant pathways, there is a paucity of information on how to effectively inhibit this class of enzymes. Here we report that UDP-(5F)-GlcNAc acts as a slow-binding, competitive inhibitor of the retaining glycosyltransferase MshA from Corynebacterium glutamicum (Ki ≈ 1.6 μM). The kinetic data are consistent with a single-step inhibition mechanism whose equilibration is slow relative to catalysis. We believe that this is the first slow-onset inhibitor to be reported for the glycosyltransferase family of enzymes. The potent inhibition of the enzyme by the fluoro-substituted substrate is consistent with the involvement of an oxocarbenium transition-state structure, which has been previously proposed for this family of enzymes. Additionally, although several members of the GT-B enzyme family, including MshA, have been shown to undergo a conformational change upon UDP-GlcNAc binding, the kinetic data are inconsistent with a two-step inhibition mechanism. This suggests that there may be other conformations of the enzyme that are useful for the design of inhibitors against the large family of GT-B glycosyltransferase enzymes.

Original languageEnglish (US)
Pages (from-to)6626-6627
Number of pages2
JournalJournal of the American Chemical Society
Volume132
Issue number19
DOIs
Publication statusPublished - May 19 2010

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ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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