Reaction: (1) 2 S-adenosyl-L-methionine + a menaquinone + reduced flavodoxin = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + an 8-methylmenaquinone + oxidized flavodoxin
(2) 2 S-adenosyl-L-methionine + a 2-demethylmenaquinone + reduced flavodoxin = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + a 2-demethyl-8-methylmenaquinone + oxidized flavodoxin
For diagram of reaction click here
Other name(s): mqnK (gene name); menK (gene name)
Systematic name: S-adenosyl-L-methionine:menaquinone C8-methyltransferase
Comments: The enzyme, found in a wide range of bacteria and archaea, is a radical SAM (AdoMet) enzyme that utilizes two molecules of S-adenosyl-L-methionine, one as the methyl group donor, and one for the creation of a 5'-deoxyadenosine radical that drives the reaction forward.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
1. Hein, S., Klimmek, O., Polly, M., Kern, M. and Simon, J. A class C radical S-adenosylmethionine methyltransferase synthesizes 8-methylmenaquinone. Mol. Microbiol. 104 (2017) 449-462. [PMID: 28164386]