Ab initio theory of helix↔coil phase transition

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2008, Vol.46 (2), p.215-225
• Main Authors: Yakubovich, A. V., Solov'yov, I. A., Solov'yov, A. V., Greiner, W.
• Format: Article
• Language: English
• Subjects: Alanine; Aminoacid polymers; Applications of Nonlinear Dynamics and Chaos Theory; Applied sciences; Atomic; Atomic and molecular physics; Atomic clusters; Biological and medical sciences; Coils; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects; Macromolecules and polymer molecules; Molecular; Molecular biophysics; Molecular Physics and Chemical Physics; Optical and Plasma Physics; Phase transitions; Physical Chemistry; Physicochemistry of polymers; Physics; Physics and Astronomy; Polypeptides; Potential energy; Quantum Information Technology; Quantum Physics; Spectroscopy/Spectrometry; Spintronics; Statistical mechanics; Studies of special atoms, molecules and their ions; clusters; Synthetic biopolymers; Transition temperature
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2007-00328-9

. In this paper, we suggest a theoretical method based on the statistical mechanics for treating the α-helix↔random coil transition in alanine polypeptides. We consider this process as a first-order phase transition and develop a theory which is free of model parameters and is based solely on fundamental physical principles. It describes essential thermodynamical properties of the system such as heat capacity, the phase transition temperature and others from the analysis of the polypeptide potential energy surface calculated as a function of two dihedral angles, responsible for the polypeptide twisting. The suggested theory is general and with some modification can be applied for the description of phase transitions in other complex molecular systems (e.g. proteins, DNA, nanotubes, atomic clusters, fullerenes).