Macromolecules, Vol.34, No.21, 7550-7557, 2001
Conformational behavior of macromolecules in solution. Homopolypeptides of alpha-aminoisobutyric acid as test cases
Solvent effects on the conformational preferences of homopolypeptides constituted by alpha -aminoisobutyric acid (polyAib) have been investigated coupling the polarizable continuum model (PCM) either to a quantum mechanical (PBE0/6-31G(d)) or to a molecular-mechanical (Amber) representation of the solute. The results allow a deeper insight into the influence of the solvent on the 3(10)/alpha -helix equilibrium in polyAib and show that PCM/Amber is a useful tool to study the conformational preferences of large peptides in condensed phase. As a matter of fact, all the PCM/Amber results are close to their PCM/PBE0 counterparts, except for some underestimation of the absolute solvation energies in polar solvents.