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Sigma Xi 2000 Student Poster Competition
This annual competition was held on April 18, 2000. The Chemistry Department had a good showing this year with 3 student poster presentations. Sigma Xi is an international research society that recognizes the importance of student involvement in research.
Students
 Ed
Musselman |
 Shea
Harper |
 Kosta
Seaford |
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Chemistry Poster Presentations
Edward Musselman (Faculty Advisor: Ricky Cox)
Poster title: "Theoretical Investigations into the Nature of
p-Stacking Interactions in Proteins"ABSTRACT:
Proteins must fold into a defined three-dimensional structure and bind
ligands to carry out their biological function. Proteins play a crucial role in all cellular processes and understanding the forces that hold these biological complexes together is important. The most overlooked and least understood noncovalent interactions in proteins involve the interplay of aromatic systems. This research focuses on how proteins recognize the adenine ring, which is a constituent of many important biological molecules. The results show that aromatic amino acids in proteins interact with the adenine ring in p-stacking complexes. Molecular mechanics calculations have been developed that accurately estimate the energy associated with these stacking interactions. This method complements existing experimental approaches that involves site-directed mutagenesis of aromatic amino acids in proteins. However, the computational approach is much faster and will allow the rapid investigation of a variety of stacking complexes. Quantum mechanical calculations were used to examine the nature of p-stacking interactions in biological systems. Initial results suggest that electrostatic interactions play a role in the formation of p-type interactions.
Shea Harper (Faculty Advisors: Ricky Cox [Chemistry] and Sterling Wright [Biology])
Poster title: "Charge Distribution of Neutral Local Anesthetics: Insights into the Block of Voltage-gated Na+ Channels"
ABSTRACT:
Local anesthetics (LAs) such as cocaine are positively charged at
physiological pH and block voltage-gated Na+ channels through putative cation-p interactions. Benzocaine, a neutral LA, has been shown to bind to the same region of the LA receptor. This raises the question of how a neutral anesthetic can share a binding site with cationic LAs. A combination of computational methods using molecular mechanics (MM) and quantum mechanics (QM) were used to determine the lowest-energy conformation and charge distribution in benzocaine and a benzocaine analog. These results were used to make a model of how benzocaine binds to the LA receptor.
Kosta Seaford (Faculty Advisor: Bommanna Loganathan)
Poster title: "PCB Congener Patterns in Pine Needles and Sediments: Observations on the Fate of PCBs in Aerobic and Anaerobic Environments."
ABSTRACT:
Ecosystems located near or at PCB contaminated sites are at the greatest risk due to exposure to this toxic chemical through air, water, contaminated soil or fish. The Linden Chemicals and Plastics (LCP) Superfund site at Brunswick, Georgia has been severely contaminated with Aroclor 1268. Sediments and pine needles (one year old) were collected at/near the site to study the fate of Aroclor 1268 PCB congeners in the anaerobic and aerobic environments. Standard analytical and quality assurance procedures were followed to measure the PCB congeners. The results revealed that total PCB congener (Aroclor 1268) concentrations in sediments and pine needles were ranged from 3000 to 5000 ng/g dry wt in sediments and 3.0 to 22.0 ng/g dry wt in pine needles. The congener composition in standard, sediment and pine needles showed similar patterns indicating the PCB congeners in Aroclor 1268 are stable in anaerobic and aerobic environments. Presence of the congeners in pine needles indicates atmospheric contamination from the superfund site.
Congratulations to Kosta Seaford for receiving the Grady Cantrell Sigma Xi Scholarship!
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This site was created by Ricky
Cox in the Department of Chemistry |
Kosta and Judge Mark Masthay