ICIQ Training Day, Master BIST-UPF

X-ray spectroscopic studies of biological methane oxidation

Soluble methane monooxygenases (sMMO) enable the biological conversion of methane to methanol. Nature’s ability to directly affect this conversion under ambient conditions is a subject of great interest in energy research, particularly for the economic utilization of natural gas. To enable this conversion, biology employs a dinculear iron active site, in which the key intermediate, known as “Q”, is able to directly cleave the strong non-polar C–H bonds of methane. The nature of Q has been the subject of intense research for more than two decades, with arguments made for both “open” or “closed” Fe₂O₂ core confirmation. Most recently, resonance Raman studies have argued that Q is best described as a symmetric closed diamond core structure. However, additional spectroscopic evidence is desirable in order to corroborate this finding. Recently, we have utilized high-energy resolution fluorescence detected x-ray absorption spectroscopy (HERFD XAS) to study MMO-Q and related model complexes. The seminar will start with a brief tutorial on both standard and advanced X-ray spectroscopic approaches. I will then discuss how these approaches have been utilized to obtain new insights into the mechanism of biological methane oxidation.