1olt | pdb_00001olt

COPROPORPHYRINOGEN III OXIDASE (HEMN) FROM ESCHERICHIA COLI IS A RADICAL SAM ENZYME.

spinqualitylabelsall models 1olt, resolution 2.07Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1olt is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SAM, SF4 Resources: FirstGlance, OCA, RCSB, PDBsum Function [HEMN_ECOLI] Involved in the heme biosynthesis. Catalyzes the anaerobic oxidative decarboxylation of propionate groups of rings A and B of coproporphyrinogen-III to yield the vinyl groups in protoporphyrinogen-IX. It can use NAD or NADP, but NAD is preferred. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed '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 sulfonium. SAM is cleaved yielding a highly oxidizing 5'-deoxyadenosyl radical. HemN, strikingly, binds a second SAM immediately adjacent to the first. It may thus successively catalyze two propionate decarboxylations. The structure of HemN reveals the cofactor geometry required for Radical SAM catalysis and sets the stage for the development of inhibitors with antibacterial function due to the uniquely bacterial occurrence of the enzyme. 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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