Methanotrophic bacteria utilize methane as their sole source of carbon and energy. The first step in their metabolic pathway is the oxidation of methane to methanol by methane monooxygenase (MMO) enzyme systems. As the only biological methane sink in an era of increased methane emissions, methanotrophs are a potential means to mitigate the deleterious effects of global warming on human health. In addition, methanotrophs can oxidize substrates besides methane, including halogenated hydrocarbons, and have been targeted for bioremediation applications. The predominant MMO in nature is particulate methane monooxygenase (pMMO), an oligomeric, integral membrane metalloenzyme. The long term goal of this project is to understand how pMMO and its homologs activate O2 for oxidation of methane and other substrates. Despite the recent identification of the pMMO active site, major questions surrounding pMMO structure and function remain to be addressed. The proposed research will focus on elucidating the atomic structure of the copper active site, the nature of the reactive species that oxidizes methane, the details of substrate, product, and reductant binding sites, and the role of the transmembrane domains. In addition, characterization of unique pMMO homologs will be pursued. The experimental approach involves spectroscopic, mechanistic, biochemical, and crystallographic characterization of native pMMO, recombinant pMMO, recombinant pMMO subunits and domains, and recombinant domains from related enzymes.
Bacteria that consume methane gas play an important role in mitigating global warming, which has deleterious effects on human health. These bacteria also are useful for bioremediation of soil and water polluted with hydrocarbon carcinogens. This project will investigate the details of how these bacteria transform methane into methanol.
|Trana, Ethan N; Nocek, Judith M; Woude, Jon Vander et al. (2016) Charge-Disproportionation Symmetry Breaking Creates a Heterodimeric Myoglobin Complex with Enhanced Affinity and Rapid Intracomplex Electron Transfer. J Am Chem Soc 138:12615-28|
|Kenney, Grace E; Goering, Anthony W; Ross, Matthew O et al. (2016) Characterization of Methanobactin from Methylosinus sp. LW4. J Am Chem Soc 138:11124-7|
|Blanchette, Craig D; Knipe, Jennifer M; Stolaroff, Joshuah K et al. (2016) Printable enzyme-embedded materials for methane to methanol conversion. Nat Commun 7:11900|
|Sirajuddin, Sarah; Rosenzweig, Amy C (2015) Enzymatic oxidation of methane. Biochemistry 54:2283-94|
|Rosenzweig, Amy C (2015) Biochemistry: Breaking methane. Nature 518:309-10|
|Austin, Rachel Narehood; Kenney, Grace E; Rosenzweig, Amy C (2014) Perspective: what is known, and not known, about the connections between alkane oxidation and metal uptake in alkanotrophs in the marine environment. Metallomics 6:1121-5|
|Sirajuddin, Sarah; Barupala, Dulmini; Helling, Stefan et al. (2014) Effects of zinc on particulate methane monooxygenase activity and structure. J Biol Chem 289:21782-94|
|Culpepper, Megen A; Cutsail 3rd, George E; Gunderson, William A et al. (2014) Identification of the valence and coordination environment of the particulate methane monooxygenase copper centers by advanced EPR characterization. J Am Chem Soc 136:11767-75|
|Lawton, Thomas J; Ham, Jungwha; Sun, Tianlin et al. (2014) Structural conservation of the B subunit in the ammonia monooxygenase/particulate methane monooxygenase superfamily. Proteins 82:2263-7|
|Culpepper, Megen A; Rosenzweig, Amy C (2014) Structure and protein-protein interactions of methanol dehydrogenase from Methylococcus capsulatus (Bath). Biochemistry 53:6211-9|
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