The identity of the active site of oxalate decarboxylase and the importance of the stability of active-site lid conformations

• DOI: 10.1042/bj20070708
• Publication Date: 2007-10-12T14:58:34Z
• Authors: Victoria J. Just; Matthew R. Burrell; Laura Bowater; Iain McRobbie; Clare E. M. Steve...; David M. Lawson; Stephen Bornemann
• Keywords: Active center

Oxalate decarboxylase (EC 4.1.1.2) catalyses the conversion of oxalate into carbon dioxide and formate. It requires manganese and, uniquely, dioxygen for catalysis. forms a homohexamer each subunit contains two similar, but distinct, sites termed 1 2. There is kinetic evidence that only site catalytically active 2 purely structural. However, kinetics enzymes with mutations in are often ambiguous all mutant have been interpreted without structural information. Nine new site-directed mutants generated four crystal structures now solved. Most targeted (i) flexibility (T165P), (ii) favoured conformation (S161A, S164A, D297A or H299A) (iii) presence (Δ162–163 Δ162–164) lid associated 1. The these were consistent being active. This was particularly striking H299A because they disrupted hydrogen bonds between neighbouring when open distant from These observations also provided first stability conformations important deletion to mimic plant oxidase led loss activity, slight elevation side reaction, implying other changes required afford reaction specificity switch. (R92A, E162A, Δ162–163 S161A) strongly support hypothesis