Quantitative structure-activity relationship (QSAR) study of the N-terminal histidine of GLP-1

CHED 1315

Taylor N. Lenton, tlenton@wellesley.edu, Wellesley College, 21 Wellesley College Rd., Wellesley, MA 02481 and David R. Haines, DHaines@Wellesley.edu, Department of Chemistry, Wellesley College, 106 Central Street, Wellesley, MA 02481.
The binding of the glucagon-like peptide-1 (GLP-1) in the pancreas is important to the insulin production process and has been shown to be strongly dependent on the N-terminal histidine of GLP-1. Several aspects of the structure of this histidine, such as its aromaticity, its pKa, and its hydrogen bonding capability have been assumed to be key to its interaction with its receptor GLP-1R. To probe this question further, analogs of histidine have been incorporated into GLP-1 and tested for biological activity. We have used this data, along with computational modeling at the semi-empirical level (AM-1), to begin development of a quantitative structure-activity relationship (QSAR) study of the N-terminal histidine. We have examined properties such as electrostatic potential, point charges, surface area, and total dipole of each analog. Correlation of these properties with IC50 and EC50 values provide a more quantitative picture of GLP-1 binding affinities.