1sg4
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(New page: 200px<br /> <applet load="1sg4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sg4, resolution 1.30Å" /> '''Crystal structure o...)
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Revision as of 17:06, 12 November 2007
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Crystal structure of human mitochondrial delta3-delta2-enoyl-CoA isomerase
Overview
The crystal structure of Delta3-Delta2-enoyl-CoA isomerase from human, mitochondria (hmEci), complexed with the substrate analogue octanoyl-CoA, has been refined at 1.3 A resolution. This enzyme takes part in the, beta-oxidation of unsaturated fatty acids by converting both cis-3 and, trans-3-enoyl-CoA esters (with variable length of the acyl group) to, trans-2-enoyl-CoA. hmEci belongs to the hydratase/isomerase (crotonase), superfamily. Most of the enzymes belonging to this superfamily are, hexamers, but hmEci is shown to be a trimer. The mode of binding of the, ligand, octanoyl-CoA, shows that the omega-end of the acyl group binds in, a hydrophobic tunnel formed by residues of the loop preceding helix H4 as, well as by side-chains of the kinked helix H9. From the structure of the, complex it can be seen that Glu136 is the only catalytic residue. The, importance of Glu136 for catalysis is confirmed by mutagenesis studies. A, cavity analysis shows the presence of two large, adjacent empty, hydrophobic cavities near the active site, which are shaped by side-chains, of helices H1, H2, H3 and H4. The structure comparison of hmEci with, structures of other superfamily members, in particular of rat, mitochondrial hydratase (crotonase) and yeast peroxisomal enoyl-CoA, isomerase, highlights the variable mode of binding of the fatty acid, moiety in this superfamily.
About this Structure
1SG4 is a Single protein structure of sequence from Homo sapiens with CO8 as ligand. Active as Dodecenoyl-CoA isomerase, with EC number 5.3.3.8 Full crystallographic information is available from OCA.
Reference
The 1.3 A crystal structure of human mitochondrial Delta3-Delta2-enoyl-CoA isomerase shows a novel mode of binding for the fatty acyl group., Partanen ST, Novikov DK, Popov AN, Mursula AM, Hiltunen JK, Wierenga RK, J Mol Biol. 2004 Sep 24;342(4):1197-208. PMID:15351645
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