9.B.280.  The Particulate Methane Monooxygenase (pMMO) Family

pMMO is a copper-dependent, integral membrane metalloenzyme complex of three subunits that converts methane to methanol in methanotrophic bacteria. pMMOs from Methylococcus (Mcc.) capsulatus (Bath) and Methylomicrobium (Mm.) alcaliphilum 20Z have have been reconstituted into bicelles without substantial alterations in the copper content or copper electronic structure. A 2.7 Å crystal structure of pMMO from Mm. alcaliphilum 20Z revealed a mononuclear copper center in the PmoB subunit and indicated that the transmembrane PmoC subunit may be conformationally flexible. Extended X-ray absorption fine structure (EXAFS) analysis of this pMMO were consistent with the observed monocopper center in the PmoB subunit (Ro et al. 2018).