National Center for
4OGG: Crystal Structure Of Arabidopsis Thaliana Dj-1d With Glyoxylate As Substrate Analog
Stereospecific mechanism of DJ-1 glyoxalases inferred from their hemithioacetal-containing crystal structures
FEBS J. (2014)
DJ-1 family proteins have recently been characterized as novel glyoxalases, although their cofactor-free catalytic mechanisms are not fully understood. In this work, we obtained crystals of Arabidopsis thaliana DJ-1d (atDJ-1d) and Homo sapiens DJ-1 (hDJ-1) covalently bound to glyoxylate, an analog of methylglyoxal, forming a hemithioacetal that presumably mimics an intermediate structure in the catalysis from methylglyoxal to lactate. The level of deuteration in lactate formation supported the proton transfer mechanism in the enzyme reaction. Differences in the enantiomeric specificity of D/L-lactacte formation observed in the DJ-1 superfamily proteins were explained by the presence of a His residue in the active site with essential Cys and Glu residues. The model for the stereospecificity was further evaluated by a molecular modeling simulation with methylglyoxal hemithioacetal superimposed on the glyoxylate hemithioacetal. The DJ-1 glyoxalase provides a unique mechanism in understanding the His residue-involved stereospecificity. This article is protected by copyright. All rights reserved.