Fig. 3

Methanogenesis via hydrogenotrophic pathway in methanogens (the Wolfe cycle), depicted via steps (i) to (viii). (i): Reaction of CO₂ with methanofuran (MFR) to produce formyl-MFR. (ii): Formyl group moves to tetraydromethanopterin (H₄MPT). (iii), (iv), (v): Formation of imine and reduction reactions. (vi): Methyl transfer from methyl-H4MPT to CoM-SH (reaction catalysed by coenzyme M (CoM) methyl-transferase). (vii): Methyl group (CH₃) reduced to methane (reaction catalysed by methyl-CoM reductase (cofactor F₄₃₀)). (viii): CoM regenerated via ferredoxin. Image reproduced with permission from [7]