Thermodynamics of polypeptide model chains

The model of a polypeptide chains was designed. The linear chain consisting of amino acid residues was approximated by an alpha carbon chain and embedded to a very flexible [3 1 0] lattice. The force field consisted of the long-range contact potential between residues and of the local helical potential. The chains were built of two types of amino acid residues, hydrophilic and hydrophobic forming a helical septets in the sequence. The Monte Carlo simulations of this model were carried out using the replica exchanges algorithm combined with the histogram method. The parameters describing the coil-to-globule transition were described and discussed. Thermodynamical properties of the polypeptide chains and of the folding transition were also determined.