Professor Michael Green, University of California, Irvine

"Exploring the factors that govern biological C-H bond activation"

About the Seminar: 

Nature’s ability to suppress energetically favorable non-productive pathways is an enigmatic aspect of biological C-H bond activation—How does an enzyme oxidize one of the most inert chemical bonds without damaging itself in the process?—We examine this issue through the lens of P450 catalysis. Cytochrome P450s play critical roles in hormone synthesis and xenobiotic metabolism. Since the discovery of P450s over five decades ago, chemists have been enamored with their ability to selectively functionalize a wide range of organic compounds. A puzzling aspect of P450 chemistry is the enzyme’s use of an electron-rich heme to catalyze the oxidation of inert hydrocarbons. Using rapid mixing and freezing techniques, we have prepared and characterized several intermediates in the P450 catalytic cycle. Through the application of a variety of spectroscopies, we have obtained insight into fundamental thermodynamic parameters as well as the electronic and geometric structures of these intermediates. Together these data suggest a mechanism by which Nature can promote C-H bond activation, while minimizing non-productive oxidations of the protein superstructure.

About the Speaker: 

Professor Green uses a mixture of theory and experiment to elucidate fundamental aspects of metalloprotein chemistry. His lab is particularly interested in a class of enzymes called cytochromes P450, which play critical roles in steroid synthesis. His interest in P450s stems not only from their biological importance but also from a desire to harness their synthetic potential: P450s catalyze the selective oxidation of inert carbon-hydrogen (C-H) bonds—A Holy Grail of chemical synthesis. For his work in this area, Prof. Green was recently elected as a Fellow of the American Association for the Advancement of Science.

Professor Green received his Ph.D. in chemistry from the University of Chicago. Upon the successful completion of his Ph.D., he went on to work at The California Institute of Technology as a postdoctoral fellow.