The goal of the Association of Chemistry Graduate Students, ACGS, is to provide opportunities and events which promote interaction, fellowship, and camaraderie among graduate students, post-docs, faculty, and staff in the chemistry department. We organize and sponsor numerous events including a department-wide volleyball tournament, various socials throughout the year, and charity events such as Trivia Night and the Toys for Tots campaign. Feel free to email us at acgs.secretary@gmail.com with any ideas, comments, or questions, especially with regard to improving how we can best serve you and the chemistry community.
Contact any of this year's officers to learn how you can get involved:
President: Bryan Frauhiger
Vice-President: Josh Beaver
Treasurer: Sarah Mueller
Secretary: Allison Hulchanski
Members of the Erie Group focus on using single molecule and biochemical methods to better understand the kinetics and thermodynamics of protein-nucleic acid interactions. Current single molecule techniques used in the lab include Atomic Force Microscopy (AFM) and Total Internal Reflection Microscopy (TIRM) techniques such as Fluorescence Resonance Energy Transfer (FRET). A major focus of our lab is the characterization of both the static and the dynamic protein-nucleic acid interactions that govern the overall repair specificity of mismatched or damaged DNA in prokaryotic and eukaryotic organisms. A few questions we are addressing include the following: How is mismatch repair initiated on some mismatches but not others? What properties of a damaged DNA substrate initiate apoptosis over mismatch repair? What roles do the mismatch repair initiation proteins, MutS and MutL, play in that separation of pathways? What are the structures/conformations of the multi protein-DNA complexes that control DNA repair? We are also characterizing a host of other protein-DNA interactions involved in DNA repair. There are projects within the group that would appeal to most areas of interest. Our group is composed of students from a variety of backgrounds and departments including chemistry, materials science, physics, and biophysics.
The pregnane X receptor (PXR), a member of the nuclear receptor superfamily, regulates the expression of drug-metabolizing enzymes in a ligand-dependent manner. The conventional view of nuclear receptor action is that ligand binding enhances the receptor's affinity for coactivator proteins, while decreasing its affinity for corepressors. To date, however, no known rigorous biophysical studies have been conducted to investigate the interaction among PXR, its coregulators, and ligands. In a collaborative work published in Biochemistry, researchers in the Thompson and Redinbo groups used steady-state total internal reflection fluorescence microscopy (TIRFM) and total internal reflection with fluorescence recovery after photobleaching to measure the thermodynamics and kinetics of the interaction between the PXR ligand binding domain and a peptide fragment of the steroid receptor coactivator-1 (SRC-1) in the presence and absence of the established PXR agonist, rifampicin.
Equilibrium dissociation and dissociation rate constants of 5 μM and 2 s-1, respectively, were obtained in the presence and absence of rifampicin, indicating that the ligand does not enhance the affinity of the PXR and SRC-1 fragments. Additionally, TIRFM was used to examine the interaction between PXR and a peptide fragment of the corepressor protein, the silencing mediator for retinoid and thyroid receptors (SMRT). An equilibrium dissociation constant of 70 μM was obtained for SMRT in the presence and absence of rifampicin. These results strongly suggest that the mechanism of ligand-dependent activation in PXR differs significantly from that seen in many other nuclear receptors.
Alternative ion activation methods in a quadrupole ion trap mass spectrometer (QITMS) have been studied by researchers in the Glish Group, to determine their utility for iTRAQ. The collisional activation methods, thermally assisted CID (TA-CID) and high amplitude short time excitation (HASTE) CID, allow the low-mass cut-off (LMCO) to be reduced to ∼10% of the parent ion mass-to-charge ratio allowing the iTRAQ reporter ions to be trapped and detected.
An alternative to CID for ion activation/dissociation in a QITMS is infrared multiphoton photodissociation (IRMPD), which can be performed at LMCOs of <10% of the parent ion mass-to-charge ratio. Published in the International Journal of Mass Spectrometry are experiments comparing the efficiency of these methods for relative quantification using iTRAQ. All methods generated the reporter ions but there were differences in overall MS/MS efficiency and the conversion efficiency to the iTRAQ reporter ions.
Members of the Waters Group, published in Angewandte Chemie, International Edition, report on the study of a minimal mimic of a protein domain that binds to type II polyproline helices through an aromatic cleft.
This binding motif mimics that of protein domains, including those important in disease states such as HIV infection and cancer. The study provides insight into the structure–function relationship in binding as well as quantitative data on the magnitude of prolyl–π interactions relevant to inhibitor design.
In the Game of Life, when the opponents in your tournament bracket include the greatest problems of our time, it takes strategy and teamwork to seek solutions. And while UNC and Duke are rivals on the basketball court, the two schools' faculty, staff and students often join forces to take on pressing global, national and local issues and challenges. One example is the collaborative research on new alternative energy, performed by the UNC/Duke Energy Frontier Research Center. This Tar Heel/Blue Devil "Dream Team" has great offense and defense, a strong roster and plays well both at home and on the road.
Bottom line: Even if they do not take the champion's crown in this year's Game of Life Tournament, the Tar Heel/Blue Devil "Dream Team" is a strong contender and will have a major influence on the outcome.
However, this formidable alliance is sometimes put on hold: come tip off at the big UNC vs. Duke basketball game tonight, we are pretty sure which shades of blue our respective students, faculty and staff will be wearing.
Histone lysine methylation is a critical marker for controlling gene expression. The position and extent of methylation controls the binding of effector proteins that determine whether the associated DNA is expressed or not. Dysregulation of histone protein methylation has been associated with a number of types of cancer, and development of inhibitors for the effector proteins is becoming an active area of research.
Mutation studies performed by scientists in the Waters Group, published in ChemBioChem, provide insight into the role of electrostatic interactions and hydrogen bonding in the differentiation of methylation states and have implications regarding the evolutionary pressure for selectivity in this protein–protein interaction. Moreover, the information from this study may help guide inhibitor development for this class of proteins.
Polymer solar cells have some noteworthy advantages over mainstream inorganic-based solar cells, such as significantly reduced material/fabrication costs, flexible substrates, and low weight of finished solar cells. Thus polymer-based solar cells have become a very intensely researched field, interfacing chemistry, physics, and engineering. Rapid progress has been made with, for example, reports of power-conversion efficiency as high as 10%.
The central question — how to rationally design polymers to reach higher efficiency — has remained at the top of research priorities. As leaders in the design and synthesis of conjugated polymers for solar cells, researchers in the You Group attempt to answer this core question in a Perspective published as a cover article in the journal Macromolecules. From their unique vantage point, Huaxing Zhou, Liqiang Yang, and Wei You comprehensively review the progress in the polymer materials design for solar cells in the past decade and a half. Additionally, they offer inspiring recommendations in the section of "Outlook and Challenges," hoping to stimulate the field to come up with new ideas to push the efficiency even higher, to 15% and beyond.