A team headed by Timothy Stemmler of Wayne State University's School of Medicine and Amy Rosenzweig at Northwestern University, has isolated a new form of a bacterial enzyme that efficiently converts methane to methyl alcohol. This enzyme is isolated from methanotropic bacteria, which are found in soil, landfills, groundwater, seawater, hot springs and even the Antarctic. The bacteria are able to carry out this difficult catalytic conversion under ambient conditions (temperature and pressure) which contrasts with the much more extreme conditions required for the commercial chemical processes used for methanol synthesis. The enzyme, called methane monooxygenase (MMO), has previously been studied primarily in a form that is soluble. The newly characterized form is found in membranes and is known as particulate MMO (pMMO). Stemmler, Rosenzweig and collaborators have recently been able to characterize its active site at SSRL. Using synchrotron based x-ray absorption spectroscopy, they probed the electronic and metrical structure of the active site and reached a surprising conclusion. While copper has long been known to be involved in some manner, an interaction with two or more metals is seen, forming a metal cluster. The team has proposed an active site - long known to contain copper - with two or more metals at its core. The multi-nuclear metal center appears to be surrounded by oxygen and/or nitrogen atoms.

To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/pmmo.html