Radical S-Adenosyl-L-methionine Chemistry in the Synthesis of Hydrogenase and Nitrogenase Metal Cofactors [Enzymology]

December 4th, 2014 by Byer, A. S., Shepard, E. M., Peters, J. W., Broderick, J. B.

Nitrogenase, [FeFe]-hydrogenase, and [Fe]-hydrogenase enzymes perform catalysis at metal cofactors with biologically unusual nonprotein ligands. The FeMo-cofactor of ni-trogenase has a MoFe7S9 cluster with a central carbon, while the H-cluster of [FeFe]-hydrogenase contains a 2Fe subcluster coordi-nated by cyanide and carbon monoxide (CO) ligands as well as dithiomethylamine; the [Fe]-hydrogenase cofactor has CO and guanylylpyr-idinol ligands at a mononuclear iron site. Intri-guingly, radical S-adenosylmethionine (SAM) enzymes are vital for the assembly of all three of these diverse cofactors. This Minireview presents and discusses the current state of knowledge of the radical SAM enzymes re-quired for synthesis of these remarkable metal cofactors.