[methyl-coenzyme M reductase]-glycine---sulfur ligase (thioglycine-forming)
Reaction(IUBMB)
ATP + sulfide + a [methyl-coenzyme M reductase]-glycine = ADP + phosphate + a [methyl-coenzyme M reductase]-thioglycine
Substrate
ATP [CPD:C00002];
sulfide [CPD:C00283];
[methyl-coenzyme M reductase]-glycine
Product
ADP [CPD:C00008];
phosphate [CPD:C00009];
[methyl-coenzyme M reductase]-thioglycine
Comment
Requires Mg2+. The enzyme is found in anaerobic methanogenic and methanotrophic archaea, where it modifies a glycine residue in EC 2.8.4.1, coenzyme-B sulfoethylthiotransferase (methyl-CoM reductase). Upon binding to its substrate, an external source of sulfide attacks the target amide bond generating a tetrahedral intermediate. The amide oxyanion attacks the gamma-phosphate of ATP, releasing ADP and forming a phosphorylated thiolate intermediate that collapses to form thioglycine and phosphate. In most organisms activity requires a second protein (TfuA) , which may allosterically activate this enzyme or assist in the delivery of sulfide to the substrate.
