Elucidation of the electron transfer environment in the MMOR FAD-binding domain from Methylosinus sporium 5.

By facilitating electron transfer to the hydroxylase diiron center, MMOR-a reductase-serves as an essential component of the catalytic cycle of soluble methane monooxygenase. Here, the X-ray structure analysis of the FAD-binding domain of MMOR identified crucial residues and its influence on the catalytic cycle.