Structural and spectroscopic insights into the mechanism of oxalate oxidase
[OXO1_HORVU] Releases hydrogen peroxide in the apoplast which may be important for cross-linking reactions in the cell wall biochemistry. May play an important role in several aspects of plant growth and defense mechanisms.
Publication Abstract from PubMed
Oxalate oxidase (EC 18.104.22.168) catalyzes the conversion of oxalate and dioxygen to hydrogen peroxide and carbon dioxide. In this study, glycolate was used as a structural analogue of oxalate to investigate substrate binding in the crystalline enzyme. The observed monodentate binding of glycolate to the active site manganese ion of oxalate oxidase is consistent with a mechanism involving C-C bond cleavage driven by superoxide anion attack on a monodentate coordinated substrate. In this mechanism, the metal serves two functions: to organize the substrates (oxalate and dioxygen) and to transiently reduce dioxygen. The observed structure further implies important roles for specific active site residues (two asparagines and one glutamine) in correctly orientating the substrates and reaction intermediates for catalysis. Combined spectroscopic, biochemical, and structural analyses of mutants confirms the importance of the asparagine residues in organizing a functional active site complex.
Structural and spectroscopic studies shed light on the mechanism of oxalate oxidase.,Opaleye O, Rose RS, Whittaker MM, Woo EJ, Whittaker JW, Pickersgill RW J Biol Chem. 2006 Mar 10;281(10):6428-33. Epub 2005 Nov 15. PMID:16291738
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.