Effects of solvents on the conformational profile of Balaram's peptide: a computational study

Abstract

The present work reports the results of a computational study aimed at characterizing the conformational profile of Balaram's peptide (Ace-Leu-Val-Val-Aib-Gly-Leu-Val-Val-NHMe) in different solvents, including chloroform, dimethyl sulfoxide, methanol and water. For this purpose, 10 micros molecular dynamics trajectories were computed in explicit solvents for each system, starting from an extended conformation. The results of the present study confirm the former NMR and CD findings and provide further insights that permit fine-tuning of the conclusions previously derived. The present results show that the peptide exhibits a helical conformation in chloroform, but a mixture of beta-hairpin and Omega-shape conformations, as the predominant structures in DMSO and MeOH. Finally, the peptide does not exhibit a preferred conformation in water, although significant populations of helical and beta-hairpin conformations are available. The present results underline the role of solvents in the conformational profile of a peptide and it is an example of the complementarity between computational methods and spectroscopy studies