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Gregory A. Voth

Distinguished Professor of Chemistry

B.S. University of Kansas

Ph.D. California Institute of Technology

Research

References

voth@chemistry.utah.edu

Greg Voth's Lab Page

Research

The research in my group involves fundamental theoretical studies of the dynamics of complex, condensed matter systems, including those of relevance to biological chemistry. A primary goal of this effort is the development and application of new theoretical methods which allow one to capitalize on the potential of the computer as a research tool. Such methods are developed, for example, to probe phenomena such as quantum charge transfer in biological environments through large-scale computer simulation. Specific research areas include:

Proton Translocation Dynamics in Biological Systems: Large-scale computer simulation studies of proton migration behavior in biological molecules are now underway using our specialized computer simulation methods. The initial targets of this research are (1) the ion channel gramicidin A which provides a model for the proton channel in the ATP synthetase complex; and (2) the enzyme carbonic anhydrase and similar enzyme systems. In both cases, the proton migration behavior is thought to occur through a shuttle of intervening water molecules as shown below. This dynamical step is key to the biological function of these systems.

In gramicidin, a "water wire" exists in the channel which spans the membrane as shown below. A proton is thought to rapidly shuttle along this wire, and it is our goal to model this process through computer simulation.

Our computational efforts in this project combine potential energy model building with specialized quantum simulation techniques to form a complete and integrated approach not found in "standard" biological simulation codes. The impact of this research will likely go beyond an understanding of the two systems described above, including many other ion channels and enzymes, proton pumps, photosynthesis, membranes, receptors, and electron transfer proteins.

Electron Transfer Dynamics in Proteins: Electron transfer is one of the most common functions of proteins. While inherently an electronic process, i.e., a transition between two electronic states, electron transfer is facilitated by nuclear motions in the protein and in the surrounding solvent. For intermolecular electron transfer such motions can bring the molecules within an appropriate distance for reaction. For both inter- and intramolecular processes, vibrational fluctuations serve to bring the energies of the electronic states sufficiently close so that transfer can occur under the Franck-Condon conditions of no change in nuclear positions or momentum. The goal of our research in this area is to develop and apply new simulation methodologies to calculate electron transfer rates in biomolecular systems such as the blue copper proteins, the photosynthetic reaction center, and synthetic electron transfer protein "mimics". The present focus is on the protein plastocyanin (shown below) in which an electron is transferred over a long distance from cytochrome f docked near the Tyr83 residue to the copper center.

References