Reaction: 2 S-adenosyl-L-methionine + protoheme + 2 reduced flavodoxin = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + anaerobilin + Fe2+ + 2 oxidized flavodoxin
For diagram of reaction click here.
Glossary: anaerobilin = (4Z,10Z,14E)-8,12-bis(2-carboxyethyl)-3,7,13,18-tetramethyl-1,2,17-trivinyl-23,24-dihydrobilin
Other name(s): chuW (gene name)
Systematic name: S-adenosyl-L-methionine:protoheme C-methyltransferase (anaerobilin-producing)
Comments: The enzyme, studied from the bacterium Escherichia coli O157:H7, is a radical SAM (AdoMet) enzyme that is involved in heme degradation and iron utilization under anaerobic conditions. The enzyme uses two SAM molecules for the reaction. The first molecule is used to generate a 5'-deoxyadenosyl radical, which abstracts a hydrogen atom from the methyl group of the second SAM molecule. The newly formed methylene radical attacks the substrate, causing a rearrangement of the porphyrin ring that results in the liberation of iron.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. LaMattina, J.W., Nix, D.B. and Lanzilotta, W.N. Radical new paradigm for heme degradation in Escherichia coli O157:H7. Proc. Natl. Acad. Sci. USA 113 (2016) 12138-12143. [PMID: 27791000]
2. LaMattina, J.W., Delrossi, M., Uy, K.G., Keul, N.D., Nix, D.B., Neelam, A.R. and Lanzilotta, W.N. Anaerobic heme degradation: ChuY Is an anaerobilin reductase that exhibits kinetic cooperativity. Biochemistry 56 (2017) 845-855. [PMID: 28045510]