2EZ8 image
Entry Detail
PDB ID:
2EZ8
Keywords:
Title:
Pyruvate oxidase variant F479W in complex with reaction intermediate 2-lactyl-thiamin diphosphate
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2005-11-10
Release Date:
2006-04-25
Method Details:
Experimental Method:
Resolution:
1.96 Å
R-Value Free:
0.17
R-Value Work:
0.14
R-Value Observed:
0.14
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Pyruvate oxidase
Mutations:F479W
Chain IDs:A, B
Chain Length:603
Number of Molecules:2
Biological Source:Lactobacillus plantarum
Primary Citation
The catalytic cycle of a thiamin diphosphate enzyme examined by cryocrystallography.
Nat.Chem.Biol. 2 324 328 (2006)
PMID: 16680160 DOI: 10.1038/nchembio788

Abstact

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.

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