Biopolymers and cell. 1988. Volume 4. № 2. 79 - 85

A. V. Kayava, V. I. Lim

EFFECT OF PEPTIDE GROUP-WATER INTERACTION ON p-STRUCTURE CONFORMATION

Summary

    An approach to estimate the effect of protein-solvent interactions on the polypeptide chain conformation is presented. The stereochemical analysis was based on the tendency of water molecules to form four hydrogen bonds with a tetrahedral orientation and was made with molecular models and computer calculations. It was shown that in the p-region of the conformational map the best polypeptide-water interaction takes place when the polypeptide chain has a polyproline conformation. We have shown that the right-handed twist of P-hairpins, determined by its intra- and interchain interactions, increases by virtue of the peptide group-water interaction. With an increase of the twist the most probable conformation of p-hairpins splits into two [3-conformations, alternating along the p-strands. The [3-structure conformation, predicted by our stereochemical analysis, agrees well with the ^-structure conformations observed in globular proteins.