Structural Analysis of a Ni-Methyl Species in Methyl-Coenzyme M Reductase from <i>Methanothermobacter marburgensis</i>

Abstract

We present the 1.2 Å resolution X-ray crystal structure of a Ni-methyl species that is a proposed catalytic intermediate in methyl-coenzyme M reductase (MCR), the enzyme that catalyzes the biological formation of methane. The methyl group is situated 2.1 Å proximal of the Ni atom of the MCR coenzyme F(430). A rearrangement of the substrate channel has been posited to bring together substrate species, but Ni(III)-methyl formation alone does not lead to any observable structural changes in the channel.