Conformational change in the thiazole and oxazoline containing cyclic octapeptides, the patellamides. Part 2. Solvent dependent conformational change

Abstract

Solvent dependent conformational change of the thiazole and oxazoline containing cyclic peptides, the patellamides, is examined by a combination of experimental and theoretical methods. A mechanism for the simultaneous formation of two type-II β-turns in the patellamides is proposed based on molecular dynamics and NOE restrained molecular dynamics studies as well as literature evidence. The effect of the solvent and desymmetrisation of the patellamides is crucial, with symmetrical patellamides in polar solvents giving the open type-I conformation, whereas symmetrical patellamides in non-polar solvents and asymmetrical patellamides in both polar and non-polar solvents give rise to the folded type-II conformation.