multiple proteins and small molecules. Among them, the radical S-adenosylmethionine
enzyme HydG, a tyrosine lyase, has been proposed to generate a complex that contains an
Fe (CO) 2 (CN) moiety that is eventually incorporated into the H-cluster. Here we describe
the characterization of an intermediate in the HydG reaction: a [4Fe–4S][(Cys) Fe (CO)(CN)]
species,'Complex A', in which a CO, a CN− and a cysteine (Cys) molecule bind to the …