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The conformational transitions in finite molecular systems, i.e. the transition from a stable 3D molecular structure to a random coil state or vice versa (also known as (un)folding process) occur or can be expected in many different complex molecular systems and in nano objects, such as polypeptides, proteins, polymers, DNA, fullerenes, nanotubes [1]. We suggest a theoretical method based on the statistical mechanics for treating the helixźrandom coil transition in polypeptides.
This method 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 [2]. We perform thorough comparison of the predictions of the statistical model with the results of molecular dynamics simulations [3]. The developed formalism is extended for the description of the helixźrandom coil transition in water environment [4]. Accounting for the water environment provided the possibility to describe hot and cold denaturation of the polypeptides and proteins within one theoretical model. Further modifications of the statistical mechanics model allowed us to describe folding-unfolding transition of single-domain proteins in water environment accounting for different pH values.
[1] A.V. Yakubovich, I.A. Solov'yov, A.V. Solov'yov, Europhysics News, 38, 10 (2007) [2] A.V. Yakubovich, I.A. Solov'yov, A.V. Solov'yov, W. Greiner, European Physical Journal D 46, 215, (2008) [3] I.A. Solov'yov, A.V. Yakubovich, A.V. Solov'yov, W. Greiner, European Physical Journal D 46, 227, (2008) [4] A.V. Yakubovich, Solov'yov, W. Greiner, Int. J. Quant. Chem. (2009) |
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