Changes of properties of the soliton with temperature under influences of structure disorder in the α-helix protein molecules with three channels

Abstract

The changes of property of solitons in α-helix protein molecules with three channels under influences of fluctuations of structure parameters and thermal perturbation of medium are extensively investigated using dynamic equations in the improved theory, numerical simulation and Runge-Kutta method. In this investigation the peculiarities of the solitons are given first in the motions of short-time and long-time and its collision features at T = 0 K and biological temperature T = 300 K. This study shows that the solutions of dynamic equations are solitons, which are very stable at T = 0 and 300 K, although its amplitudes and velocity are somewhat decreased relative to that at T = 0 K, the soliton can transport over 1000 amino acid residues, its lifetime is, at least, 120 ps. Subsequently, studies are made of the changes of properties of the soliton with variations of temperature of the medium and fluctuations of structure parameters including mass sequence of amino acid residues and the coupling constant, force constant, dipole–dipole interaction, chain–chain interaction and ground state energy in the α-helix proteins. The investigations indicate that the soliton has high thermal stability and can transport along the molecular chains retaining amplitude, energy and velocity, although the fluctuations of the structure parameters and temperature of the medium increase continually. However, the solitons disperse in larger fluctuations at T = 300 K and higher temperatures than 315 K. Thus it is determined that the critical temperature of the soliton is 315 K. Finally reasons are given for the generation of high thermal stability of the soliton and the correctness of the improved model is demonstrated. It is concluded that the soliton in the improved model is very robust against structure disorder and thermal perturbation of the α-helix protein molecules at 300 K, and is a possible carrier of bio-energy transport, and the improved model is maybe a candidate for the mechanism of this transport.

Keywords:

• energy transport
• thermal stability
• temperature effect
• numerical simulation

Acknowledgements

The authors would like to thank the National Natural Science foundation of China for financial support (grant No: 20104034).