- The nature of the exchange coupling between high-spin Fe(III) heme o3 and CuBII in Escherichia coli quinol oxidase, cytochrome bo3: MCD and EPR studies. Cheesman, M.R., Oganesyan, V.S., Watmough, N.J., Butler, C.S., Thomson, A.J. J. Am. Chem. Soc. (2004)