The stability of secondary structure in aqueous solution

Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.

Abstract

Conformational thermodynamics determine the ability of peptides to adopt specific secondary structural motifs. In aqueous solution, the preference for a particular motif is strongly influenced by the solvent. We will describe results from our ongoing systematic study of the factors which influence stability of peptide conformations in aqueous solution. Through the use of peptide models containing the simplest amino acids, e.g., ala, gly, pro and val, we have focussed on the "intrinsic" features of stability as determined solely by peptide backbone conformational preferences, peptide backbone hydrogen bonding and solvent-peptide interactions.

In this lecture results for the stability of the hydrogen bond, reverse turns, alpha helices and beta sheets will be presented. Contributions to the stability from solvent induced forces, peptide conformational energetics and entropic factors will be separated to provide a physical picture of the resulting thermodynamics.