2ez4
From Proteopedia
Pyruvate oxidase variant F479W
Overview
Enzymes that use the cofactor thiamin diphosphate (ThDP, 1), the biologically active form of vitamin B(1), are involved in numerous metabolic pathways in all organisms. Although a theory of the cofactor's underlying reaction mechanism has been established over the last five decades, the three-dimensional structures of most major reaction intermediates of ThDP enzymes have remained elusive. Here, we report the X-ray structures of key intermediates in the oxidative decarboxylation of pyruvate, a central reaction in carbon metabolism catalyzed by the ThDP- and flavin-dependent enzyme pyruvate oxidase (POX)3 from Lactobacillus plantarum. The structures of 2-lactyl-ThDP (LThDP, 2) and its stable phosphonate analog, of 2-hydroxyethyl-ThDP (HEThDP, 3) enamine and of 2-acetyl-ThDP (AcThDP, 4; all shown bound to the enzyme's active site) provide profound insights into the chemical mechanisms and the stereochemical course of thiamin catalysis. These snapshots also suggest a mechanism for a phosphate-linked acyl transfer coupled to electron transfer in a radical reaction of pyruvate oxidase.
About this Structure
2EZ4 is a Single protein structure of sequence from Lactobacillus plantarum. Full crystallographic information is available from OCA.
Reference
The catalytic cycle of a thiamin diphosphate enzyme examined by cryocrystallography., Wille G, Meyer D, Steinmetz A, Hinze E, Golbik R, Tittmann K, Nat Chem Biol. 2006 Jun;2(6):324-8. Epub 2006 May 7. PMID:16680160 Page seeded by OCA on Sun May 4 03:16:22 2008
