Conformational properties of β-residue-containing oligopeptides in apolar solvent

Molecular dynamics simulations carried out on short linear peptides incorporating β-Ala residues, namely Boc-β-Ala-Phe-OMe (1) and Boc-Met-β-Ala-Phe-OMe (2), reveal a markedly different conformational-dynamical behaviour. The tripeptide (2), showing free energy minima deeper than the dipeptide is predicted to be characterized by long-lived conformers. The present theoretical results may help in rationalizing experimental (IR, NMR) results on (1) and (2) and definitely show the importance of a dynamical approach for a correct interpretation and prediction of the conformational behaviour in solution even for relatively small molecules.