A MODEL FOR THE LOW-SPIN, NONHEME, THIOLATE-LIGATED IRON SITE OF NITRILE HYDRATASE

A synthetic analogue of nitrile hydratase, [Fe-III(ADIT)(2)]-Cl (2), i s described. Nitrile hydratase is the first and only current example o f a metalloenzyme containing a single non-heme Fe in a mixed N/S-ligat ed coordination site. Like the enzyme, 2 possesses short Fe-S distance s, EPR parameters indicative of an S = 1/2 ground state, and a single band near 710 nm in its electronic spectrum. Low-spin complexes of thi s type are extremely rare.