Fig. 3.

Crystal structure of Methyl coenzyme M reductase (MCR). (A) Ribbon representation of the Methanothermococcus thermolithotrophicus MCR III (PDB 5N1Q). The different colors represent each of the α, β and γ subunits. The insert is a close-up view of the active site which shows the arrangement of the modified residues. The tetrahydrocorphinoid (coenzyme F430) is represented as a space-filling model. CoB-SH and CoM-SH are also shown. (B) Stick models of modified residues commonly found in the MCR active site.