类蛋白质分子的二级结构对力学行为的影响

采用Kolinski等建立的类蛋白质分子的格点模型,研究了由典型的(HHPPHPP)x重复单元构成、含有α螺旋结构的类蛋白质分子链在拉伸过程中的构象性质和力学行为.发现不同强度的α螺旋相互作用会直接影响其拉伸过程.α螺旋相互作用强的类蛋白质分子链,具有更低的内能,更小的应力,在拉伸过程中更容易失去紧密接触对,同时也更容易被拉成“棒状”结构,但在整个拉伸过程中,α螺旋结构且能保持稳定;还发现类蛋白质分子的链长对拉伸也有影响,对较长的类蛋白质分子链,其内能更低,弹性力更小,自由能更大,紧密接触对的含量比例也更高,而“棒状化”程度较小.这些研究能够帮助我们加深对蛋白质分子的构象和弹性力学行为的理解.

EFFECTS OF SECONDARY STRUCTURE ON ELASTIC BEHAVIOR OF PROTEIN-LIKE CHAINS

Conformational properties and elastic behavior of protein-like chains are investigated using the protein-like lattice model built by Kolinski et al.Here the sequence of (HHPPHPP)_x is adopted,and different chain length and different α helical interaction energy are also considered.It is found that the α helical interaction energy directly influences the interior conformation and elastic behavior of protein-like chains in the process of tensile elongation.The chains with large α helical interaction energy have lower energy and less elastic force,and they are more easily to lose contacts and more easily to take the “rod" structure.Moreover,α helical structure remains unchanged in the process of tensile elongation.In the meantime,the length of chains also influences the conformational properties of chains in the elongation process.The long chains have lower energy,less elastic force,more Helmholtz energy,and larger number of contacts.However,they are more difficult to take the “rod" structure.This investigation can help us to understand the interior conformations and elastic behavior of real proteins in the process of elongation.