Sikorski Andrzej, Romiszowski Piotr
Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Biopolymers. 2003 Jul;69(3):391-8. doi: 10.1002/bip.10368.
The lattice approximation of a heteropolymer chain as a model of a single polypeptide was used in the computer simulation. The residues of a model polypeptide were represented by the chain of alpha-carbons located on a very flexible [310] lattice. The force field that mimic the intramolecular interactions contained the long-range contact potential between the residues and the local preferences in forming helical structures. The chain consisted of two types of residues that had different hydrophobicity. The simulations were performed by means of the Replica Exchange Monte Carlo method combined with the Histogram method. The series of simulations were carried out to investigate the influence of both components of the force field on the transition temperature and the characteristics of the coil-to-globule transition. The properties of low-temperature ordered structures were determined. The thermodynamical description of the model chain was also given. The phase transition was found to be sharp and cooperative for longer chains and strong helical potential. The collapsed globule contained the strongly hydrophobic residues inside the globule while the remaining residues were mainly located close to the globule surface.
在计算机模拟中，使用异聚物链的晶格近似作为单条多肽链的模型。模型多肽的残基由位于非常灵活的[310]晶格上的α-碳原子链表示。模拟分子内相互作用的力场包含残基之间的长程接触势以及形成螺旋结构的局部偏好。该链由两种具有不同疏水性的残基组成。通过复制交换蒙特卡罗方法结合直方图方法进行模拟。进行了一系列模拟，以研究力场的两个组成部分对转变温度以及线圈到球体转变特性的影响。确定了低温有序结构的性质。还给出了模型链的热力学描述。发现对于较长的链和强螺旋势，相变是尖锐且协同的。塌陷的球体在球体内包含强疏水残基，而其余残基主要位于球体表面附近。
