CROFTS, Antony R.

Department of Physiology & Biophysics
Ph.D. (1965) Cambridge University (England)

    Research Topics

• Proton Pumps of Photosynthetic Bacteria
• Mechanisms of Reduction of Plastoquinone Photo System II in Chloroplasts
• Molecular Architecture of the Catalytic Sites of Electron Transfer Chains

    Research Interests  

   Research interests cover the mechanism of photosynthetic energy conversion, at the level of the photochemical reactions and secondary electron transport, in photosynthetic bacteria, chloroplasts and intact green plants. Most of our work has been concerned with understanding how the enzymic complexes of the photosynthetic electron transfer chains act as proton pumps, and how the proton gradients generated as a result of electron transfer are used in the synthesis of ATP and other energy-utilizing reactions. The overall mechanisms of these processes are now fairly clear - the enzymes act as classical Mitchellian proton pumps. Our more recent work has, therefore, been directed towards understanding mechanisms in greater detail at the molecular level. Of particular importance in several of the complexes are the reactions by which they interact with the pool of quinone, which acts as a shuttle of reducing equivalents between complexes. We are also interested in the mechanism of oxygen evolution. We have established a battery of biophysical methods for looking at the detailed kinetic and thermodynamic parameters which describe the mechanisms for several of these catalytic sites, but this "black-box" approach provides limited insight into detailed molecular mechanism. We have recently established a number of collaborative projects in which we are combining forces with colleagues skilled in the arts of molecular engineering, and are designing and constructing specific mutants to test hypotheses about the role of particular amino-acid residues in catalysis. This approach, combined with structural studies, including measurements of topology, protein structural prediction, X-ray crystallography, and construction of atomic models based on homology with solved structures, promises to lead to a detailed understanding of the molecular basis of catalysis in this important group of enzymes.

    Key Words    Biomass Conversion, Site-Directed Mutagenesis, Active Sites and Receptors, Molecular Modeling, Photosynthesis and Biophysical Techniques, Structural Biology

    Current Research Funding   NIH, USDA, DOE

BTC Members