Folding propensity of anoplin: A molecular dynamics study of the native peptide and four mutated isoforms

Anoplin, a cationic decapeptide amide GLLKRIKTLLNH2 derived from venom sac of the solitary wasp Anoplius samariensis has been investigated through Molecular Dynamics. The wild-type (WT) and four isoforms were simulated both in water and in the membranemimicking solvent trifluoroethanol (TFE). In water all the investigated species, found to be in rapid equilibrium between different conformational states, can be considered as unfolded. On the other hand, in TFE all the systems enhance their rigidity and, in general, show a-helix as the main folded conformation. Interestingly, a semiquantitative thermodynamic analysis has suggested that the folding driving force is not always the same being in some cases (e.g., the WT Anoplin) of entropic nature and in other cases of energetic nature. VC 2015 Wiley Periodicals, Inc. Biopolymers 103: 692–701, 2015.