Molecular Physics and Chemical Physics

The European Physical Journal D

, Volume 46, Issue 2, pp 215-225

First online:

Ab initio theory of helix↔coil phase transition

  • A. V. YakubovichAffiliated withFrankfurt Institute for Advanced Studies
  • , I. A. Solov'yovAffiliated withFrankfurt Institute for Advanced Studies
  • , A. V. Solov'yovAffiliated withFrankfurt Institute for Advanced Studies Email author 
  • , W. GreinerAffiliated withFrankfurt Institute for Advanced Studies

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Abstract.

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).

PACS.

82.60.Fa Heat capacities and heats of phase transitions 87.15.He Dynamics and conformational changes 64.70.Nd Structural transitions in nanoscale materials 64.60.-i General studies of phase transitions