Biochemistry of Methyl-Coenzyme M Reductase: The Nickel Metalloenzyme that Catalyzes the Final Step in Synthesis and the First Step in Anaerobic Oxidation of the Greenhouse Gas Methane - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 128

product, CoBS-SCoM (MCR silent , PDB code 1hbm) [ 48 , 52 ]. Structures have also
been determined of the enzyme in the presence of CoBSH analogs, which differ in the
number of carbon atoms in the heptanoyl group of the native substrate [ 53 ].
MCR (Figure 2 ) forms a functional dimer, (

ʱʲʳ ) 2 , which is composed of a series

of ʱ helices shaped like an American football with dimension of 120 Å by 85 Å by

80 Å [ 52 ] . The ʱ , ʱ ', ʲ , and ʲ ' subunits associate tightly into a core to which the ʳ

and ʳ ' subunits attach on either side.

Figure 2 Structure of methyl-coenzyme M reductase. (a) The functional dimer, ( ) 2 .(b) The

substrate channel. Reprinted by permission from [ 65 ]; copyright 2012 World Scientific
Publishing Co.

ʱʲʳ