Investigating the Formation of Hydrogen Bonds in Gamma-Aminobutryic Acid
Alison Fullilove1, April E. Hardin2, Genevieve Verville2, Austin Dorris2, and Nathan I. Hammer2
1Mississippi INBRE Research Scholar, Division of Mathematics and Sciences, Delta State University, Cleveland, MS
2Department of Chemistry and Biochemistry, University of Mississippi, University, MS
Gamma-Aminobutyric Acid, commonly referred to as GABA, serves as an inhibitory neurotransmitter in the central nervous system. Produced from glutamic acid, GABA is responsible for sending chemical messages from the brain to the nervous system, which helps to reduce anxiety and depression, in addition to stimulating sleep. GABA utilizes hydrogen bonding, allowing it to bind to GABAA and GABAB receptors. Here, Raman Spectroscopy is used to analyze the hydrogen bond network created by GABA and water. The spectrum of solid GABA was compared to solution state spectra in order to analyze the effects of hydrogen bonding on the vibrational normal modes. Moreover, solutions of GABA and water were acidified to a pH of 6 using HCl and analyzed to probe any potential changes in hydrogen bonding that arise from changing the pH. Theoretical calculations were run with the B3LYP hybrid functional and the 6-311++g(2df,2pd) basis set on a single GABA molecule in isolation. Calculations were also run on GABA with the addition of up to three water molecules to investigate possible hydrogen bonding sites. Additionally, the relative energies of each system were compared to determine which configuration possessed the lowest energy. Simulated Raman Spectra was compared to the experimental Raman spectra to analyze GABA’s hydrogen bonding capabilities.