Moessbauer Studies of the Membrane-Associated Methane Monooxygenase from Methylococcus capsulatus Bath: Evidence for a Diiron Center

摘要

Methane monooxygenase (MMO) catalyzes the energy-dependent oxidation of methane to methanol in methanotrophic bacteria. In these organisms, two different methane monooxygenases have been identified, namely, a membrane-associated or particulate MMO (pMMO) and a cytoplasmic or soluble MMO (sMMO). In metha-notrophs that express both forms of the enzyme, the copper concentration during growth dictates which MMO is expressed. In cells cultured under a low copper/biomass ratio, the sMMO is predominately expressed, whereas cells cultured at higher copper/ biomass ratios exclusively express the pMMO (sMMO is not transcribed).