Bacterial Reaction Centers with New Photochemical Properties

Arizona State University, Scottsdale AZ

Investigators

Abstract

The Chemistry of Life Sciences Program funds Professor James Allen of Arizona State University for research entitled "Bacterial Reaction Centers with New Photochemical Properties." In all photosynthetic systems, the primary energy transduction event is the light-induced generation of a charge-separated state in a pigment-protein complex. Although the specific pathways vary among organisms, the general pattern is remarkably conserved, and an understanding of these processes serves as the basis for current designs of artificial systems that mimic the photosynthetic process. The reaction center from Rhodobacter sphaeroides can be used as a model system to incorporate features of photosystem II such as a highly oxidizing primary donor. The recent development of a redox active mononuclear Mn cofactor provides the opportunity to study novel manganese cofactors and to introduce new light-driven reactions into this photosystem. The first objective of the proposed research is to design novel Mn cofactors and correlate the properties of these cofactors with different experimental observables. The second objective is to use this model system to probe key properties of the Mn4Ca cluster of photosystem II that is the site of water oxidation. Overall, the molecular insight gained from these studies should have a general impact on developing design principles for metalloenzymes, understanding electron transfer mechanisms in photosynthesis, and improving energy conversion technologies. Our research promotes progress in science by providing wider opportunities for participation in undergraduate research, meeting challenges in undergraduate education by writing textbooks, creating a curriculum for a new interdisciplinary graduate program, fostering scientific communication to the general public, and sponsoring outreach efforts to students who have limited opportunities for scientific research. This project is receiving co-funding from the Biomolecular Dynamics, Structure and Function Cluster in the Division of Molecular and Cellular Biosciences.