Mechanistic Investigation of CO activation by Nitrogenase

University Of California-Irvine, Irvine CA

Investigators

Abstract

Developing sustainable sources of carbon fuels while confronting the accumulation of carbon wastes (CO and CO2) from the combustion of carbon fuels are competing global challenges. With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Professor Markus Ribbe and Professor Yilin Hu from the University of California, Irvine, to investigate the detailed chemical mechanism for how the nitrogenase enzyme reduces CO and CO2 to form larger hydrocarbon compounds. The knowledge acquired through this research informs the design of novel catalysts that recycle carbon wastes into usable fuels, thereby simultaneously combating energy- and environment-related problems. This project provides multidisciplinary education and training across a broad range of experimental and computational techniques to postgraduate researchers, and graduate and undergraduate students. Research and education are integrated through research opportunities across all education levels and through incorporation of microbial biotechnology into classroom teaching. Various outreach events and programs are developed, including Science Saturdays at UC Irvine, to engage middle school students, including those from underrepresented minority communities, to learn about global energy and environmental problems, and potential biotechnological solutions to these problems. The inability to generate distinct substrate- or intermediate-bound states has remained a major roadblock for mechanistic investigations of nitrogenase. This proposal utilizes a novel approach to uncouple the binding of CO or CO-derived intermediates from the subsequent turnover, thereby providing a unique tool for the generation of successive snapshots along the reaction pathway of CO reduction via controlled delivery of electron(s)/proton(s) to CO or CO-derived species. A strategic combination of chemical, biochemical and spectroscopic approaches will then be used to analyze these defined snapshots in hopes of (1) obtaining insights into the C1 pathway that converts CO to CH4; (2) defining the C1 conformation for the binding and coupling of the second CO; and (3) identifying the mechanism of carbon chain extension. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.