1OLT

Coproporphyrinogen III oxidase (HemN) from Escherichia coli is a Radical SAM enzyme.

1OLT の概要

• エントリーDOI: 10.2210/pdb1olt/pdb
• 分子名称: OXYGEN-INDEPENDENT COPROPORPHYRINOGEN III OXIDASE, IRON/SULFUR CLUSTER, S-ADENOSYLMETHIONINE, ... (4 entities in total)
• 機能のキーワード: heme biosynthesis, decarboxylase, radical sam enzyme, 4fe- 4s cluster, s-adenosyl-l-methionine, oxidoreductase
• 由来する生物種: ESCHERICHIA COLI
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 53930.34

構造登録者

Layer, G.,Moser, J.,Heinz, D.W.,Jahn, D.,Schubert, W.-D. (登録日: 2003-08-13, 公開日: 2003-12-04, 最終更新日: 2024-05-08)

主引用文献

Layer, G.,Moser, J.,Heinz, D.W.,Jahn, D.,Schubert, W.-D.
Crystal Structure of Coproporphyrinogen III Oxidase Reveals Cofactor Geometry of Radical Sam Enzymes
Embo J., 22:6214-, 2003

PubMed Abstract: '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.

PubMed: 14633981
DOI: 10.1093/EMBOJ/CDG598

実験手法

X-RAY DIFFRACTION (2.07 Å)