Environmental Molecular Sciences Laboratory

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Structure and function of the membrane-bound copper-dependent methane monooxygenase in lipid nanodiscs

Date: 
Monday, June 15, 2020
Principal Investigator: 
Amy Rosenzweig
Lead Institution: 
Northwestern University
Project ID: 
51533
Abstract: 

Particulate methane monooxygenase (pMMO) is the primary enzyme used for methane metabolism by methane-consuming bacteria known as methanotrophs. pMMO is a copper-dependent, membrane-bound metalloenzyme that oxidizes methane to methanol by an unknown mechanism. Recently, we were able to obtain pMMO particles that retained methane oxidation activity by embedding them in lipid nanodiscs. We then determined a 2.6 Å resolution structure of pMMO from Methylococcus capsulatus (Bath) from this preparation using cryoEM, revealing the structure of regions disordered in crystal structures due to the use of detergents for solubilization. These regions include a putative novel metal binding site and clear density for several lipid molecules that may mediate activity. We believe that there is much more to learned about pMMO using cryoEM. Planned experiments include studying pMMO orthologs in copper-loaded and apo forms, and in the presence of substrates, products, and quinol reductants.