Mechanism of Microbial Oxidation of Methane
Industrial processes to convert methane to other fuel molecules and chemical feedstocks are inefficient, requiring substantial energy inputs. In contrast, methantrophic bacteria efficiently convert methane to methanol, which can then be converted to other fuels and chemicals. This methane to methanol conversion is catalyzed by methane mono-oxygenase (MMO) enzymes. A team led by Timothy Stemmler of Wayne State University and Amy Rosenzweig of Northwestern University used an x-ray spectroscopy station at the Stanford Synchrotron Radiation Lightsource to demonstrate that the active site of MMOs in the methanotroph Methylococcus capsulatus contains two copper atoms. They also showed that the active site is in a soluble domain of the enzyme not the membrane bound component. This resolves long-standing uncertainties about whether the active site contains an iron or a copper atom, and how many metal atoms are in the active site. These results will enable the design of enzyme-based systems for large-scale conversion of methane to other molecules.
R. Balasubramanian, et al., “Oxidation of methane by a biological dicopper centre”, Nature, 465, 115-119 (2010).