Metals are an essential component of approximately 50% of all proteins, with functions ranging from energy storage and metabolism to molecular transport and cellular signaling. However, due to the complexity of these metalloprotein systems, many of which contain multiple, distinct metal centers, the mechanisms of action often remain elusive. This research will develop a novel approach towards studying these reactions by combining laboratory experiments with computational chemistry to better understand how these metalloproteins function. This methodology will be applied to the study of hydrogen production and oxidation in natural and engineered enzymes, with future potential applications for alternative energy, sustainable fuels, carbon dioxide fixation, and nitrogen cycling, among others. Furthermore, the research objectives of this proposal are integrated with education and outreach activities, with far-reaching impact for both science and society. The interdisciplinary nature of the work, involving aspects of biology, chemistry, and physics, renders the subject accessible to a wide variety of audiences. The educational plan will expose a broad range of students from underrepresented racial/ethnic groups and with disabilities to modern chemistry research in an immersive fashion, with the objective of building a diverse, career-oriented pipeline of STEM talent. General-interest seminars for adult audiences will be presented with aims of improving scientific literacy, increasing awareness, and better engaging the community in contemporary research being carried out at OSU and across the world.
With this award from the Chemistry of Life Processes Program in the Division of Chemistry, Dr. Hannah Shafaat from The Ohio State University will study enzymatic mechanisms in metalloproteins using computationally-guided resonance Raman spectroscopy (CGRRS). By harnessing the selectivity and sensitivity of resonance Raman spectroscopy performed on a highly tunable, state-of-the-art instrument, important information on the structures of catalytic intermediates, including protonation state, bond order, and coordination mode, will be obtained. Site-selective and state-specific excitation in conjunction with theoretical predictions of spectroscopic properties will be used to characterize intermediates and transient species that are inaccessible by conventional approaches. Small molecule activation reactions at metalloenzyme active sites, including proton reduction, hydrogen oxidation, and oxygen reduction in hydrogenases and models, will be investigated to demonstrate the utility of this experimental-computational approach and identify key structural motifs during catalysis. This synergistic methodology will be broadly applicable to the study of many classes of enzymes, particularly those containing multiple metallocofactors, such as nitrogenase and carbon monoxide dehydrogenase. Using CGRRS, it will be possible to gain molecular-level insight into complex reaction mechanisms and begin to understand how metalloproteins are able to function as some of the most efficient catalysts known.
