A putative [Fe.sup.2+]-bound persulfenate intermediate in cysteine dioxygenase

A 1.4 Angstrom resolution crystal structure of the [Fe.sup.2+]-dependent enzyme cysteine dioxygenase (CDO) containing putative intermediate persulfenate trapped in its active site pocket is reported. The results revealed that the Fe-proximal oxygen atom might be involved in the primary oxidation event to give a unique three-membered Fe-S-O cyclic intermediate and facilitate isomerization of the persulfenate to the sulfinate product.