pMMO
pMMO, or particulate methane monooxygenase, is a copper-containing enzyme complex that catalyzes the first and rate-limiting step of aerobic methane oxidation in methanotrophic bacteria. It is membrane-associated, localized in intracytoplasmic membranes, and formed by the pmoCAB gene cluster encoding the PmoA, PmoB, and PmoC subunits that assemble into a functional oligomer, typically a trimer of heterotrimers.
The enzyme converts methane to methanol using molecular oxygen, with electrons supplied from the electron transport
pMMO is copper-dependent; the precise active site arrangement has been the subject of ongoing investigation. Structural
Methanotrophic bacteria that express pMMO include species such as Methylococcus capsulatus, Methylosinus trichosporium, and Methylocystis species.
Understanding pMMO has implications for methane mitigation and biocatalysis. Challenges include the membrane-bound nature of the