Deng Li, Zhou Peng, Zhao Yurong, Wang Yanting, Xu Hai
Centre for Bioengineering and Biotechnology, China University of Petroleum (East China) , 66 Changjiang West Road, Qingdao 266580, China.
J Phys Chem B. 2014 Oct 30;118(43):12501-10. doi: 10.1021/jp506385j. Epub 2014 Oct 20.
In order to understand how microscopic molecular interactions between short peptides determine their mesoscopic self-assembled morphology, we studied the microscopic assembled structures of the short peptides I4K2 and KI4K, which have the same amino acid composition but different sequences, by using all-atom replica exchange molecular dynamics simulation. We found that, at room temperature, the difference in amino acid sequence does not apparently alter their strong propensity of forming β-sheets but does strongly affect their assembled stable structures and their appearance probabilities. These differences result from the competition between the electrostatic and hydrophobic interactions among the side chains of the molecules, which are linked up by hydrogen bonds formed between neighboring peptide backbones. Our simulation results not only reveal the molecular origin of the self-assembled morphological difference between I4K2 and KI4K but also demonstrate in general the subtle balance between electrostatic, hydrophobic, and hydrogen bonding interactions in short-peptide self-assembly.
为了理解短肽之间的微观分子相互作用如何决定其介观自组装形态，我们通过全原子复制交换分子动力学模拟研究了具有相同氨基酸组成但序列不同的短肽I4K2和KI4K的微观组装结构。我们发现，在室温下，氨基酸序列的差异并没有明显改变它们形成β-折叠的强烈倾向，但确实强烈影响它们的组装稳定结构及其出现概率。这些差异源于分子侧链之间静电和疏水相互作用的竞争，这些侧链通过相邻肽主链之间形成的氢键连接起来。我们的模拟结果不仅揭示了I4K2和KI4K自组装形态差异的分子起源，还总体上证明了短肽自组装中静电、疏水和氢键相互作用之间的微妙平衡。
