2c3p: Difference between revisions

Revision as of 19:58, 18 December 2007

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

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

2C3P is a Single protein structure of sequence from Desulfovibrio africanus with MG, CA, SF4 and 1TP as ligands. Active as Pyruvate synthase, with EC number 1.2.7.1 Known structural/functional Site: . 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

Page seeded by OCA on Tue Dec 18 19:08:24 2007

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OCA

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-[[Image:2c3p.gif|left|200px]]<br />
+[[Image:2c3p.gif|left|200px]]<br /><applet load="2c3p" size="450" color="white" frame="true" align="right" spinBox="true"
-<applet load="2c3p" size="450" color="white" frame="true" align="right" spinBox="true"
 caption="2c3p, resolution 2.33&Aring;" />
 '''CRYSTAL STRUCTURE OF THE FREE RADICAL INTERMEDIATE OF PYRUVATE:FERREDOXIN OXIDOREDUCTASE FROM DESULFOVIBRIO AFRICANUS'''<br />
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 ==About this Structure==
-C3P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Desulfovibrio_africanus Desulfovibrio africanus] with MG, CA, SF4 and 1TP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pyruvate_synthase Pyruvate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.2.7.1 1.2.7.1] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2C3P OCA].
+C3P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Desulfovibrio_africanus Desulfovibrio africanus] with MG, CA, SF4 and 1TP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pyruvate_synthase Pyruvate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.2.7.1 1.2.7.1] Known structural/functional Site: <scene name='pdbsite=AC1:Ca Binding Site For Chain B'>AC1</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2C3P OCA].
 ==Reference==
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 [[Category: tpp-dependent enzyme]]
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