RUI: Calculating Acid Dissociation Constants in Aqueous Solution

Hamilton College, Clinton NY

Investigators

Abstract

George Shields of Hamilton College is supported by an RUI award from the Theoretical and Computational Chemistry program for research involving the calculation of acid dissociation constants in aqueous solution. The goal of the research is to identify the best computational methods and procedures for the accurate calculation of pKa values. The PI is using a variety of quantum chemistry methods and thermodynamic cycles to carry out a systematic study of a broad range of molecules. The specific effects of hydrogen bonding of explicit water molecules to the ions in solution are also being investigated. In one particularly unique feature of the research program, pKa values for histidines in a wide array of peptide sequences are being investigated, allowing theoretical prediction of conditions under which both nitrogens will become protonated, information that is not yet available experimentally. The project is having a broader impact in the training of future scientists and is being carried out entirely with undergraduates, many of whom are already involved in a number of projects established by the PI, some of which have been funded by NSF, such as the NSF-STEP program. The equipment to be used in the research has been established through the MERCURY Consortium, also headed up by the PI and partially supported by the NSF, which brings together a number of faculty at several undergraduate institutions in the region.