2c3o
CRYSTAL STRUCTURE OF THE FREE RADICAL INTERMEDIATE OF PYRUVATE:FERREDOXIN OXIDOREDUCTASE FROM DESULFOVIBRIO AFRICANUS
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OverviewOverview
Pyruvate-ferredoxin oxidoreductases (PFOR) are unique among thiamine, pyrophosphate (ThDP)-containing enzymes in giving rise to a rather stable, cofactor-based free-radical species upon the decarboxylation of their, first substrate, pyruvate. We have obtained snapshots of unreacted and, partially reacted (probably as a tetrahedral intermediate) pyruvate-PFOR, complexes at different time intervals. We conclude that pyruvate, decarboxylation involves very limited substrate-to-product movements but a, significant displacement of the thiazolium moiety of ThDP. In this, respect, PFOR seems to differ substantially from other ThDP-containing, enzymes, such as transketolase and pyruvate decarboxylase. In addition, exposure of PFOR to oxygen in the presence of pyruvate results in, significant inhibition of catalytic activity, both in solution and in the, crystals. Examination of the crystal structure of inhibited PFOR suggests, that the loss of activity results from oxime formation at the 4' amino, substituent of the pyrimidine moiety of ThDP.
About this StructureAbout this Structure
2C3O is a Single protein structure of sequence from Desulfovibrio africanus with MG, CA, SF4, TPP and PYR as ligands. Active as Pyruvate synthase, with EC number 1.2.7.1 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
ReferenceReference
Flexibility of thiamine diphosphate revealed by kinetic crystallographic studies of the reaction of pyruvate-ferredoxin oxidoreductase with pyruvate., Cavazza C, Contreras-Martel C, Pieulle L, Chabriere E, Hatchikian EC, Fontecilla-Camps JC, Structure. 2006 Feb;14(2):217-24. PMID:16472741
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