Office: A741A Life Sciences Annex
Lab: A751,A743 Life Sciences Annex
Our laboratory studies proteins: most particularly protein-DNA and protein-ligand interactions, protein folding and stability, and protein structure and conformation in solution.
Our work is primarily focused on the Type I DNA polymerases from Thermus aquaticus (Taq/Klentaq) and E. coli (Pol I/Klenow). The DNA polymerases from E. coli and T. aquaticus are a homologous mesophilic-thermophilic pair of proteins. Their molecular structures and basic catalytic functions are highly homologous, yet the Taq enzyme works near the boiling point of water, while the E. coli enzyme is irreversibly destroyed by exposure to 50oC. We directly and comparatively examine the DNA binding, protein folding, and global structural characteristics of these two species of DNA polymerases with the goal of delineating the exact differences and similarities between the two proteins in order to understand what features are necessary to achieve high temperature stability and activity for a DNA polymerase. These studies include characterizations of DNA binding using fluorescence anisotropy and titration calorimetry, characterizations of stability using thermal and chemical denaturation methods, and characterization of structural and conformational changes using small angle X-ray scattering, and analytical ultracentrifugation.
We also examine similar questions in other protein systems, including HIV reverse transcriptase, Deinococcus radiodurans Pol I polymerase, Rec A, the mammalian adipocyte lipid binding protein (ALBP), and aspartate transcarbamylase
Yang, Y, and LiCata, VJ, 2011, Interactions of replication versus repair DNA substrates with the Pol I DNA polymerases from Escherichia coli and Thermus aquaticus. Biophys. Chem., 159: 188-193.
LiCata, VJ, and Liu, C-C, 2011, Analysis of free energy versus temperature curves in protein folding and macromolecular interactions. Methods Enzymol., 488: 219-238.
Wowor, AJ, Datta, K, Brown, HS, Thompson, GS, Ray, S, Grove, A, and LiCata, VJ, 2010, Thermodynamics of the DNA structural selectivity of the Pol I DNA polymerases from Escherichia coli and Thermus aquaticus, Biophys J., 98: 3015-3024.
Deredge, DJ, Baker, JT, Datta, K, and LiCata, VJ, 2010, The gluatmate effect on DNA binding by Pol I DNA polymerases: osmotic stress and the effective reversal of salt linkage. J. Mol. Biol., 401: 223-238.
Datta, K, Johnson, NP, LiCata, VJ, and von Hippel, PH, 2009, Local conformations and competitive binding affinities of single- and double-stranded primer-template DNA at the polymerization and editing active sites of DNA polymerases, J. Biol. Chem., 284:17180-17193.
Liu, C-C, Richard, A.J, Datta, K, and LiCata, V.J., 2008, Temperature variable heat capacity effects in protein-DNA interactions, Biophys. J. 94: 3258-3265.
LiCata, VJ, and Wowor, AJ, 2008, Applications of Fluorescence Anisotropy to the Study of Protein-DNA Interactions, Methods in Cell Biology, Vol. 84, 243-262.