Component of the methyl-coenzyme M reductase (MCR) I that catalyzes the reductive cleavage of methyl-coenzyme M (CoM-S-CH3 or 2-(methylthio)ethanesulfonate) using coenzyme B (CoB or 7-mercaptoheptanoylthreonine phosphate) as reductant which results in the production of methane and the mixed heterodisulfide of CoB and CoM (CoM-S-S-CoB). This is the final step in methanogenesis. coenzyme B + methyl-coenzyme M = coenzyme M-coenzyme B heterodisulfide + methane Binds 1 coenzyme F430 non-covalently per MCR heterotrimeric complex. Coenzyme F430 is a yellow nickel porphinoid. Methyl-coenzyme-M reductase is activated when the enzyme-bound coenzyme F430 is reduced, probably to the Ni(I) oxidation state. Optimum pH is 7.0. Optimum temperature is 60 degrees Celsius. One-carbon metabolism; methyl-coenzyme M reduction; methane from methyl-coenzyme M: step 1/1. MCR from M.thermophila is a heterotrimer composed of an alpha, a beta, and a gamma subunit. Belongs to the methyl-coenzyme M reductase beta subunit family.