Faculty Research
Joe Bradshaw
Metalloporphyrin Interaction with DNA
Research in the group involves the synthesis of neutral "tentacle" water-soluble porphyrins to be tested as possible intercalators of DNA. Metalloporphyrins of this nature have been shown to be tumor specific and thus have potential as possible tumor therapy agents. It has been recently demonstrated that the synthesis of these neutral porphyrins containing poly-alcohol functionalities to achieve water-solubility can be carried out (Figure 1). The rational for the proposed investigation is that the cationic natures of the porphyrins that have been studied thus far (+2 to +4) most probably influence DNA binding due to charge considerations alone. Furthermore, by utilizing neutral water-soluble porphyrins, changing the metal (M = Ni2+, Zn2+, Cu2+, Mn3+, Fe3+, Co3+) within the porphyrin core can provide insight into question of the metal center/oxidation state role in DNA binding. The specific interaction of these new metalloporphyrins and a “hair-pin” oligonucleotide are studied using polyacrylamide gel electrophoresis, PAGE, to determine whether inside/outside binding or cleavage of the oligonucleotide occurs. This project will provide preliminary evidence into the ability of these novel water-soluble porphyrins to interact with DNA bases. This research is funded by a J. D. Patterson Grant.
Figure 1
Tim Hayes
Rb family protein complexes in the terminal differentiation of 3T3L1 cells
My research interests center on the mechanisms involved in the permanent exit of cells from the cell cycle as they terminally differentiate. Cells that previously proliferated in response to external signals now respond to those same signals in a different way. What changes in the cell to alter its response?
The major project in my lab looks at this question using the terminal differentiation of pre-adipocytes as a model. Pre-adipocytes proliferate rapidly and can be cultured like fibroblasts. When they are contact inhibited they can be treated with 2 signals, insulin and IBMX and will respond by differentiating. Over the course of the next 4 days they express fat cell proteins, produce lipid droplets and turn into adipocytes. During this time many of the cells divide once or twice but once this period is past they are post-mitotic- they never divide again.
Preadipocytes express the 3 members of the retinoblastoma family- the retinoblastoma protein (RB), p107 and p130. RB was first characterized as the protein which is inactivated in the tumor hereditary retinoblastoma. It acts to halt the onset of S phase by binding to and inactivating the E2F family transcription factors. Late in G1, RB is phosphorylated by the cyclin-dependent kinases, causing it to release the E2Fs, which then stimulate transcription of genes necessary for S phase. The expression of RB is unchanged throughout preadipocyte differentiation. Before the cells are stimulated to differentiate, the expression of p130 is high and p107 is low. Over the first 24 hours after stimulation, the levels of p130 decline while those of p107 increase dramatically. As the cells differentiate, the levels revert back to high p130 and low p107.
It appears that the increase in p107 is critical for preadipocytes to exit the cell cycle and terminally differentiate. My lab is working on experiments designed to identify the proteins to which p107 binds, based on the assumption that p107 acts through relatively stable interactions with other proteins, similar to RB. Our experiments utilize cell culture, protein techniques (chromatography, electrophoresis, Western blotting, etc.) and molecular biology techniques (transfection, mRNA isolation, PCR, etc.) This research is funded by an Arkansas INBRE Grant.
Joe Jeffers
The Life and Works of Frederick Sanger, Nobel Laureate in Chemistry 1958, Nobel Laureate in Chemistry 1980
Dr. Frederick Sanger was awarded the Nobel Prize in Chemistry in 1958 for his work in determining the structure of insulin, the first protein molecule sequenced. He became only the third two-time recipient of the Nobel Prize when he shared the 1980 Nobel Prize in Chemistry for developing techniques for sequencing DNA molecules. Dr. Sanger worked first in the Biochemistry Department at Cambridge University in England. Then he worked at the Medical Research Council Laboratory of Molecular Biology in Cambridge. I have interviewed Dr. Sanger and many of his colleagues and family members. I continue research to prepare articles for the Bulletin for the History of Chemistry and to write a biography of Frederick Sanger. This research is funded by a J. D. Patterson Grant.
Marty Perry
Computational Docking Studies of Nitroanisoles with CYP2E1
Research efforts focus on computational strategies for understanding protein-ligand interactions in important biomedical processes. We employ molecular modeling techniques to discover how substrates bind in protein active sites relying on experimental data to complement our work. Molecular modeling of intermolecular interactions are performed on computer workstations using Sybyl software from Tripos, Inc. Several modules (energy minimization, docking, molecular dynamics simulation, etc.) within the Sybyl environment are utilized. Our most recent efforts are in collaboration with Dr. Grover Miller in the Biochemistry Department at UAMS. We are currently studying CYP2E1 (P450 or CYP for a particular isoform), a mammalian cytochrome P450 enzyme which oxidizes a structurally diverse class of endogenous and exogenous (xenobiotic) compounds. A majority of studies have focused on the role of CYP2E1 in Phase I metabolism of xenobiotic compounds, e.g. drugs, food additives, and environmental contaminants. Growing evidence also supports an important physiological role for CYP2E1 in gluconeogenesis. CYP2E1 is regulated similarly to enzymes contributing to gluconeogenesis in relation to starvation and diabetes and in fact, recognizes precursors to gluconeogenesis, acetone, acetol (1-hydroxyacetone), and fatty acids as substrates. This research is funded by a J. D. Patterson Grant and by an Arkansas INBRE Grant.
Last update: June 2008