Chemistry Faculty:
Marly K. Eidsness
Assistant Professor
E-mail: eidsness@uga.edu
Biographical Information
B.F.A., California State University, Long Beach, 1977
B.A., California State University, Long Beach, 1982
Ph.D., University of Cincinnati, 1985
Postdoctoral Fellow, Stanford University, 1985-1986
Postdoctoral Fellow, University of Illinois, Urbana, 1986-1987
Research Interests
The synthesis of proteins in vivo is a linear process, proceeding from the N- to the C- termini of the polypeptide chain. Acquiring the proper functional fold of the protein usually requires the assistance of molecular chaperones. We are interested in protein folding and we study trigger factor, an E. coli chaperone and cis-trans prolyl isomerase. Among its diverse roles in the cell, trigger factor is essential for viability at low temperatures (4°C) and it binds to the 50S ribosome where nascent polypeptide chains exit. Trigger factor is the first chaperone newly synthesized proteins encounter. The pivotal role of cis-trans proline in protein folding (see the Figure) is apparent in the abundance of prolyl isomerases in all phyla. Our research integrates chemistry, biochemistry, and molecular biology to address structural and functional questions of trigger factor. For structural studies, we are expressing trigger factor as separate functional domains that will be characterized by NMR spectroscopy and x-ray crystallography via collaborations. Our functional studies involve folding of trigger factor substrates (e.g. is proline isomerization an early protein folding event?) through in vitro translation experiments with designed polypeptide substrates and spectroscopic detection. We also take a global, cellular perspective to probe cooperative interactions between trigger factor and other chaperones, dnaKJ and GroEL/ES. We use proteomics tools to make two-dimensional protein maps from cells grown in the absence and presence of trigger factor and other chaperones. Identifying proteins that change on these maps is the basis for protein-protein interaction experiments (phage display and two-hybrid methods) with the goal of deciphering molecular mechanisms of trigger factor under various stress conditions.
Another research project involves protein stability and redox potential tuning using rubredoxin (the smallest iron-sulfur protein) as a model system for protein engineering. We find that chimeric rubredoxins with interchanged amino acid sequences from mesophilic and hyperthermophilic proteins do not have thermostabilities one might expect based upon their sequences. This indicates that global, rather than local interactions dominate thermostability in rubredoxins. In contrast, redox potential tuning in rubredoxins is controlled in large part by the identity of a single non-polar amino acid, either valine or alanine at position 44 near the iron-sulfur center.
Publications
Bougault, C. M.; Eidsness, M. K.; Prestegard, J. H. " Hydrogen Bonds in Rubredoxins from Mesophilic and Hyperthermophilic Organisms " Biochemistry, 2003, 42, 4357-4372.
Ergenekan, C. E.; Thomas, D.; Fischer, J. T.; Tan, M.; Eidsness, M. K.; Kang, C. H.; Ichiye, T. " Prediction of Reduction Potential Changes in Rubredoxin: A Molecular Mechanics Approach " Biophys. J., 2003, 85, 2818-2829.