2pvz
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(New page: 200px<br /><applet load="2pvz" size="350" color="white" frame="true" align="right" spinBox="true" caption="2pvz, resolution 1.97Å" /> '''Crystal structure of...)
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Revision as of 10:33, 23 January 2008
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Crystal structure of methylaconitate isomerase PrpF from Shewanella oneidensis
Overview
In bacteria, the dehydration of 2-methylcitrate to yield 2-methylaconitate, in the 2-methylcitric acid cycle is catalyzed by a cofactor-less (PrpD), enzyme or by an aconitase-like (AcnD) enzyme. Bacteria that use AcnD also, require the function of the PrpF protein, whose function was previously, unknown. To gain insights into the function of PrpF, the three-dimensional, crystal structure of the PrpF protein from the bacterium Shewanella, oneidensis was solved at 2.0 A resolution. The protein fold of PrpF is, strikingly similar to those of the non-PLP-dependent diaminopimelate, epimerase from Haemophilus influenzae, a putative proline racemase from, Brucella melitensis, and to a recently deposited structure of a, hypothetical protein from Pseudomonas aeruginosa. Results from in vitro, studies show that PrpF isomerizes trans-aconitate to cis-aconitate. It is, proposed that PrpF catalysis of the cis-trans isomerization proceeds, through a base-catalyzed proton abstraction coupled with a rotation about, C2-C3 bond of 2-methylaconitate, and that residue Lys73 is critical for, PrpF function. The newly identified function of PrpF as a, non-PLP-dependent isomerase, together with the fact that PrpD-containing, bacteria do not require PrpF, suggest that the isomer of 2-methylaconitate, that serves as a substrate of aconitase must have the same stereochemistry, as that synthesized by PrpD. From this, it follows that the, 2-methylaconitate isomer generated by AcnD is not a substrate of, aconitase, and that PrpF is required to generate the correct isomer. As a, consequence, the isomerase activity of PrpF may now be viewed as an, integral part of the 2-methylcitric acid cycle.
About this Structure
2PVZ is a Single protein structure of sequence from Shewanella oneidensis with and as ligands. Full crystallographic information is available from OCA.
Reference
The three-dimensional crystal structure of the PrpF protein of Shewanella oneidensis complexed with trans-aconitate: insights into its biological function., Garvey GS, Rocco CJ, Escalante-Semerena JC, Rayment I, Protein Sci. 2007 Jul;16(7):1274-84. Epub 2007 Jun 13. PMID:17567742
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