Sh. Nilar et Ts. Pluta, HYDROGEN-BONDING CAPABILITIES-BASED ON POLARIZABILITY STUDIES OF MODEL PEPTIDE SYSTEMS, Journal of the American Chemical Society, 117(50), 1995, pp. 12603-12607
The peptide bond is a fundamental unit in understanding the interactio
ns between proteins and the surrounding medium. In this paper, models
for the main chain and polar and nopolar side chains of amino acid res
idues were carefully chosen and complexes with each other and water cl
usters were calculated using a Monte Carlo/Simulated Annealing techniq
ue. The dipole polarizabilities, a, of these clusters were evaluated w
ithin the Coupled Perturbed Hartree-Fock (CPI-IF) method using special
basis sets designed for the evaluation of electric response propertie
s. The change in the interaction modified average polarizability per e
lectron for each of the interacting subsystems, Delta Delta alpha, is
defined in the text, evaluated for each of the interacting systems, an
d used as a measure of the strength of the hydrogen bond and the ident
ification of the hydrogen bond donor in each complex. The relative imp
ortance of main-chain, side-chain, and solvent effects in the models u
sed to describe protein folding is discussed.