1olt
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(New page: 200px<br /> <applet load="1olt" size="450" color="white" frame="true" align="right" spinBox="true" caption="1olt, resolution 2.07Å" /> '''COPROPORPHYRINOGEN ...)
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Revision as of 15:34, 29 October 2007
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COPROPORPHYRINOGEN III OXIDASE (HEMN) FROM ESCHERICHIA COLI IS A RADICAL SAM ENZYME.
Overview
'Radical SAM' enzymes generate catalytic radicals by combining a 4Fe-4S, cluster and S-adenosylmethionine (SAM) in close proximity. We present the, first crystal structure of a Radical SAM enzyme, that of HemN, the, Escherichia coli oxygen-independent coproporphyrinogen III oxidase, at, 2.07 A resolution. HemN catalyzes the essential conversion of, coproporphyrinogen III to protoporphyrinogen IX during heme biosynthesis., HemN binds a 4Fe-4S cluster through three cysteine residues conserved in, all Radical SAM enzymes. A juxtaposed SAM coordinates the fourth Fe ion, through its amide nitrogen and carboxylate oxygen. The SAM sulfonium, sulfur is near both the Fe (3.5 A) and a neighboring sulfur of the cluster, (3.6 A), allowing single electron transfer from the 4Fe-4S cluster to the, SAM ... [(full description)]
About this Structure
1OLT is a [Single protein] structure of sequence from [[1]] with SAM and SF4 as [ligands]. Full crystallographic information is available from [OCA].
Reference
Crystal structure of coproporphyrinogen III oxidase reveals cofactor geometry of Radical SAM enzymes., Layer G, Moser J, Heinz DW, Jahn D, Schubert WD, EMBO J. 2003 Dec 1;22(23):6214-24. PMID:14633981
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