Dr. Solon Georghiou
ProfessorPh.D., University of Manchester, 1968
Office: 216 Nielsen Physics Building
Phone: 865-974-7835
Fax: 865-974-7843
sgeorghi@utk.edu
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Dr. Solon GeorghiouProfessorPh.D., University of Manchester, 1968 Office: 216 Nielsen Physics Building Phone: 865-974-7835 Fax: 865-974-7843 sgeorghi@utk.edu |
MOLECULAR BIOPHYSICSPhotophysics of biomoleculesThe Molecular Biophysics group is studying the photophysics of biomolecules. This fast-growing research area is making exciting contributions to the interfacing of physics and biology. Our first area of research emphasis is the study of the dynamic and excited-state properties of DNA. There are two major incentives for doing this research: (1) formation of defects in DNA by both light and ionizing radiation involves electronic excited states, with some defects resulting in genetic mutations that cause inheritable diseases; and (2) the dynamic nature of DNA, i.e. how conformationally flexible and deformable DNA is, is of major importance in protein-DNA interactions, packaging of DNA into chromosomes, gene regulation at a distance, and the intercalation of a number of drugs between the DNA base pairs (i.e. building blocks). Both steady-state and time-resolved fluorescence measurements are being made. In the latter, which are done in collaboration with Dr. Joseph Beechem, Vanderbilt University, very fast polarized ultraviolet laser pulses are used to excite DNA and the polarization of the emitted light is followed over a time range of picoseconds to nanoseconds. In the first such study ever done, we have detected large-amplitude concerted motions in the interior of DNA; these are thermally-induced and appear to be associated with compressional waves which propagate along the double helix. The emerging view of DNA is that of a dynamic, very deformable structure. The implications of these findings are of paramount importance with regard to the ability of DNA to perform its multifunctional task. Other research investigates the nature of the forces responsible for the interaction between adjacent bases in DNA, and the modulation of the dynamics of the DNA helix by environmental factors. The second research area is the interaction of melittin, a protein toxin, with model biological membranes. The results of these studies are of broader importance, because the amphiphilic alpha helical conformation of this protein when in membranes pertains also to other important classes of proteins, which include peptide hormones, signal peptides and apolipoproteins. The technique of stopped-flow fluorometry is used in which a melittin solution is mixed with a membrane solution within a few milliseconds and the fluorescence emission of the amino acid tryptophan of melittin or that of an external fluorescent probe is measured as a function of time. The primary goals are to establish (1) the nature of the forces involved in the protein-membrane interaction and (2) the effects of the protein on the structure and dynamics of membranes. Recent discoveries by our research group include the rigidification of membranes by the protein, the lipid (i.e. membrane component) -selectivity of the protein, and the generation and propagation of protein-induced structural and dynamic membrane perturbations over a long distance. Brief VitaProfessor Solon Georghiou, also Adjunct Professor of Biochemistry, received a B.S. in Physics from the University of Athens (Greece) in 1962, and M.S. and Ph.D. degrees in Photophysics from the University of Manchester (England) in 1965 and 1968, respectively. After doing postdoctoral work at the University of Minnesota in Minneapolis and the Johns Hopkins University, he joined the faculty of the Physics Department of the University of Tennessee in 1973.Selected Publications
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