2c3y

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spinqualitylabelsall models 2c3y, resolution 1.93Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THE RADICAL FORM OF PYRUVATE:FERREDOXIN OXIDOREDUCTASE FROM DESULFOVIBRIO AFRICANUS

Overview

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 Structure

2C3Y is a Single protein structure of sequence from Desulfovibrio africanus with , , , and as ligands. Active as Pyruvate synthase, with EC number 1.2.7.1 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

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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