From micelles to bicelles: Effect of the membrane on particulate methane monooxygenase activity.

Autor:	Ro SY; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Ross MO; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Deng YW; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Batelu S; the Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201., Lawton TJ; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Hurley JD; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Stemmler TL; the Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201., Hoffman BM; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and., Rosenzweig AC; From the Departments of Molecular Biosciences and Chemistry, Northwestern University, Evanston, Illinois 60208 and amyr@northwestern.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2018 Jul 06; Vol. 293 (27), pp. 10457-10465. Date of Electronic Publication: 2018 May 08.
DOI:	10.1074/jbc.RA118.003348
Abstrakt:	Particulate methane monooxygenase (pMMO) is a copper-dependent integral membrane metalloenzyme that converts methane to methanol in methanotrophic bacteria. Studies of isolated pMMO have been hindered by loss of enzymatic activity upon its removal from the native membrane. To characterize pMMO in a membrane-like environment, we reconstituted pMMOs from Methylococcus ( Mcc. ) capsulatus (Bath) and Methylomicrobium ( Mm. ) alcaliphilum 20Z into bicelles. Reconstitution into bicelles recovers methane oxidation activity lost upon detergent solubilization and purification without substantial alterations to copper content or copper electronic structure, as observed by electron paramagnetic resonance (EPR) spectroscopy. These findings suggest that loss of pMMO activity upon isolation is due to removal from the membranes rather than caused by loss of the catalytic copper ions. A 2.7 Å resolution crystal structure of pMMO from Mm. alcaliphilum 20Z reveals a mononuclear copper center in the PmoB subunit and indicates that the transmembrane PmoC subunit may be conformationally flexible. Finally, results from extended X-ray absorption fine structure (EXAFS) analysis of pMMO from Mm. alcaliphilum 20Z were consistent with the observed monocopper center in the PmoB subunit. These results underscore the importance of studying membrane proteins in a membrane-like environment and provide valuable insight into pMMO function. (© 2018 Ro et al.)
Databáze:	MEDLINE
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