Research Topics
Department of Plant Biology
Ph.D. (1971) Bristol University (England)
Research Topics
Research Interests
The light-activatable nature of the photosynthetic process provides unequalled opportunities for studying all the essential functions of proteins encountered in biological energy transduction and enzyme activity. Electron and proton transfer are central to biological energy transduction but electron transfer is also the key function of many enzymes with important commercial potential, such as P450's, and intra-protein transfer is the basis of almost all biological catalysis.
The structures of the key membrane proteins in photosynthetic energy conversion, the reaction center (RC) and the cytochrome bc1 complex (Cyt bc1), are now known to atomic resolution, from X-ray crystallography. Thus, the detailed mechanisms whereby photosynthesis converts light into electrochemical free energy with high efficiency and yield are accessible, and provide ideal systems for understanding the role of protein in determining specificity and optimization of cofactor function and catalysis. Working with intact membranes and isolated RCs and Cyt bc1, we are using biophysical techniques (e.g., fast kinetic spectroscopy, EPR, photovoltage measurements), molecular genetics (protein engineering) and computational methods to study: (1) charge separating and stabilizing electron transfer reactions; (2) proton uptake and intra-protein proton transfer reactions; (3) electrostatics and dynamics in proteins; (4) cofactor (quinone) binding and modulation of function by protein; (5) electrogenic steps in electron and proton transfer processes, using direct electrical measurements.
Key Words
Site-Directed Mutagenesis, Protein Purification and Characterization, Herbicide
Mechanisms, Photosynthesis and Biophysical Techniques, Active Sites and
Receptors, Biocatalysis
Current Research Funding
NSF, NIH