The Escherichia coli cysG gene encodes the multifunctional protein, siroheme synthase.
Previously, the E. coli cysG gene product had been shown to sequentially methylate uro'gen III to produce precorrin-2, hence it was given the trivial name uro'gen III methylase. We now report that in addition to methylase activity, the CysG protein catalyses both the NAD+ dependent oxidation of precorrin-2 to sirohydrochlorin, but also the insertion of iron into this oxidized intermediate, thereby producing siroheme. Thus CysG is a multifunctional protein solely responsible for siroheme synthesis from uro'gen III in E. coli, and accordingly is renamed siroheme synthase.
Spencer
J B
JB
Department of Chemistry, Texas A&M University, College Station 77843-3255.
Stolowich
N J
NJ
Roessner
C A
CA
Scott
A I
AI
D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D006418:Heme / Q000031:analogs & derivatives / Q000096:biosynthesis; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009243:NAD / Q000378:metabolism / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014577:Uroporphyrinogens / Q000378:metabolism
D009097:Multienzyme Complexes; D014577:Uroporphyrinogens; D009243:NAD; D006418:Heme; C009272:siroheme; D008780:Methyltransferases; C060508:uroporphyrin-III C-methyltransferase