α-Helix propensities of homo-oligomers in aqueous solution studied by multicanonical algorithm

Helix–coil transitions of homo-oligomers in aqueous solution are studied by multicanonical Monte Carlo simulations. The solvation effects are represented by the term that is proportional to the solvent-accessible surface area of the peptides. Homo-oligomers of length 10 are considered for two characteristic amino acids, alanine and glycine, which are helix former and helix breaker, respectively. It is shown that the helix–coil transition temperature for homo-alanine in water is considerably lower than in gas phase. The helix propagation parameter s and nucleation parameter σ for both alanine and glycine are calculated and shown to be in remarkable agreement with experimental results.