Albany 2015:Book of Abstracts
June 9-13 2015
©Adenine Press (2012)
Helix-Coil Transitions in heteropolymers. The constrained annealing approach
Theory of helix-coil transition in heterogenius biopolymers has been constructed on the base of the GMPC model (Hairyan et al. 1990, 1995); Morozov et al. 2004; Badasyan et al. 2005) using the constrained annealing approach, developed by M. Serva and G. Paladin (1993)) An expression for the free energy of the heteropolymer has been obtained by averaging the transfer matrix of homopolymeric GMPC with redefined energy and conformational parameters (Tonoyan et al 2014). An algorithm for calculation of the melting curve of heteropolymeric system was obtained. The melting curves of homopolymeric and heteropolymeric systems were compared. It was shown the bimodal heterogeneity in energy of hydrogen bonding qualitatively defines the main melting properties of random heteropolymer.
We obtained the melting curves for bimodal heterogeneous biopolymers, with heterogeneity either caused by difference in hydrogen bonding formation energies, or heterogeneity in the number of conformations. It was shown that the overall properties of the melting curves coincide, the melting interval is approximately the same for both cases. No more than two peaks exist on the differential melting curve.
Thus multicomponent heterogeneity, including heterogeneity in the number of conformations cannot be responsible for the fine structure. Therefore, we assume that the fine structure is either a consequence of solvent effect, or correlation in the sequence.
This research has been supported by 13-1F343 Grant from State Committee of Science Ministry of Education and Science of Armenia.
Hairyan, Sh.A., Mamasakhlisov, E.Sh. & Morozov, V.F. (1995). The helix-coil transition in polypeptides: a microscopic approach. II. Biopolymers, 35(1), 75-84.
Morozov, V.F., Badasyan, A.V., Grigoryan, A.V., Sahakyan, M.A., & Mamasakhlisov, Y.Sh. (2004).Stacking and hydrogen bonding: DNA cooperativity at melting. Biopolymers, 75,434-439.
Badasyan, A.V., Grigoryan, A.V., Mamasakhlisov, E.Sh., Benight, A.S, & Morozov, V.F. (2005). The helix-coil transition in heterogeneous double stranded DNA: Microcanonical method. Journal of Chemical Physics, 123, doi: 10.1063/1.2727456
Serva, M., & Paladin, G. (1993). Gibbs thermodyinamic potentials for disordered systems. Physical Review Letters, 70, 105-108.
Tonoyan, Sh. A., Asatryan, A.V., Mamasakhlisov, Y. Sh., & Morozov, V. F. (2014). Helix-coil transition in biopolymers with multicomponent heterogeneity of energy and number of conformations. Journal of Contemporary Physics, 49, 132-137.
Shushanik A. Tonoyan
Department of Molecular Physics