1olt
COPROPORPHYRINOGEN III OXIDASE (HEMN) FROM ESCHERICHIA COLI IS A RADICAL SAM ENZYME.
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OverviewOverview
'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 StructureAbout this Structure
1OLT is a [Single protein] structure of sequence from [Escherichia coli] with SAM and SF4 as [ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [OCA].
ReferenceReference
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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