Influence of the solvent on the conformational-dependent properties of random-coil polypeptides. 1. The mean-square of the end-to-end distance and of the dipole moment

Conformational energies for the N-acetyl-N'-methylamides of the 20 natural amino acids were calculated, including the solvent effects, as functions of the angles Phi and psi for rotation of the main chain and for six positions chi super(1) of the C super( alpha )-C super( beta ) bond in the side chain (fixed values for chi super(2), chi super(3),...). the computed energies were used to evaluate the mean-square end-to-end distance and mean-square dipole moment of homopolypeptides of the 20 natural amino acids. Ten proteins and three enzymes of current interest were also studied. Slight differences in both properties are found on taking the effects of solvent into consideration. Comparison with other computational and experimental results is made.