Structural and enzymatic analysis of MshA from Corynebacterium glutamicum: Substrate-assisted catalysis

Matthew W. Vetting, Patrick A. Frantom, John S. Blanchard

Research output: Contribution to journalArticle

81 Scopus citations

Abstract

The glycosyltransferase termed MshA catalyzes the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to 1-L-myo-inositol-1-phosphate in the first committed step of mycothiol biosynthesis. The structure of MshA from Corynebacterium glutamicum was determined both in the absence of substrates and in a complex with UDP and 1-L-myo-inositol-1-phosphate. MshA belongs to the GT-B structural family whose members have a two-domain structure with both domains exhibiting a Rossman-type fold. Binding of the donor sugar to the C-terminal domain produces a 97° rotational reorientation of the N-terminal domain relative to the C-terminal domain, clamping down on UDP and generating the binding site for 1-L-myo-inositol-1-phosphate. The structure highlights the residues important in binding of UDP-N-acetylglucosamine and 1-L-myo-inositol-1-phosphate. Molecular models of the ternary complex suggest a mechanism in which the β-phosphate of the substrate, UDP-N- acetylglucosamine, promotes the nucleophilic attack of the 3-hydroxyl group of 1-L-myo-inositol-1-phosphate while at the same time promoting the cleavage of the sugar nucleotide bond.

Original languageEnglish (US)
Pages (from-to)15834-15844
Number of pages11
JournalJournal of Biological Chemistry
Volume283
Issue number23
DOIs
Publication statusPublished - Jun 6 2008

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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