Structural Biology

Dr. Sunyoung Kim (skim3@lsuhsc.edu)
— Assistant Professor
Dr. Kim is studying how protein structure determines protein function. Dr. Kim performs biochemical and biophysical analyses of proteins with related structures but different functions to search for the fundamental physical and chemical properties that allow them to perform their respective binding and catalytic activities. By studying dynamic chemical and structural changes in enzymes with innovative spectroscopic tools, her laboratory continues to gain insight into the mechanisms behind how distinct protein families involved in DNA repair, cell cycle, and signal transduction, exhibit similar structures, yet perform different, cellular roles. Click here to learn more about Dr. Kim's research.

Dr. Thang Chiu (tchiu@lsuhsc.edu)
— Assistant Professor
Understanding the fundamental processes that govern protein folding, and the role of conformational dynamics in protein function, are vitally important for modern medicine, as protein misfolding or alternatively folded states can result in diseases, or provide new targets for therapeutic intervention. To study the role of conformational dynamics in protein function, we are crystallizing and determining the structures of various prolyl peptidases, which have biological functions ranging from cancer to diabetes and psychological disorders. We do this by trapping each enzyme in different conformational states through crystallization, and determining their crystal structures. We also pursuing similar efforts to study key proteins involved in HIV/AIDS and innate immunity, which have potential benefits for millions of people worldwide. To accomplish these studies we use modern molecular biology methods to design and produce recombinant proteins in bacterial or insect cells, purify them to homogeneity, and crystallize and determine their three dimensional structures by X-ray crystallography. We corroborate our structural interpretations of the biological function by using site-directed mutagenesis to knock out or introduce interactions at critical active site or interface residues, and study the altered proteins crystallographically and biochemically. To study protein folding, we have engineered mutations into the headpiece of the villin headpiece subdomain, in the process producing a protein that folds within 700 ns, the fastest to date, and only two times slower than its theoretical speed limit. We hypothesized that this speed increase and extra stability were the result of removal of unfavorable electrostatic interactions from the wild-type peptide, and are engineering new mutations to study their effects on protein stability and folding kinetics. Click here to learn more about Dr. Chiu's research.

Dr. David Worthylake (dworth@lsuhsc.edu)
— Assistant Professor
Dr. Worthylake's research utilizes a structural approach to focus on the molecular mechanisms that destabilize cell-cell junctions, a necessary step in cancer metastasis. To accomplish his studies Dr. Worthylake uses recombinant protein that is expressed and purified from bacteria. The purified proteins are studied to identify novel binding partners in cells. The proteins and their binding partners are tested for their ability to crystallize alone and in complexes. X-ray crystallography is used to determine the three-dimensional structures of crystallized proteins. Site directed mutagenesis is employed to identify molecular interactions that are required for binding and biological activity. Click here to learn more about Dr. Worthylake's research.

Dr. Edward N. Wojcik (ewojci@lsuhsc.edu)
— Assistant Professor
Extra centrosomes are commonly seen in cancer cells where they have been shown to contribute to genetic instability. The biochemical pathway that regulates centrosome duplication is poorly understood. Dr. Wojcik is using both genetic and biochemical analyses of specific proteins involved in centrosome duplication to learn more about centrosome and cytoskeletal regulation during cell division. His laboratory performs molecular and genetic analyses of Drosophila melanogaster coupled with biochemical and biophysical analysis of protein function. Click here to learn more about Dr. Wojcik's research.