Anisotropic formation mechanism and nanomechanics for the self-assembly process of cross-β peptides  

作　　者：邓礼 赵玉荣 周鹏 徐海 王延颋 

机构地区：[1]Center for Bioengineering and Biotechnology, China University of Petroleum (East China) [2]CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences (CAS) [3]School of Physical Sciences, University of Chinese Academy of Sciences

出　　处：《Chinese Physics B》2017年第12期18-31,共14页中国物理B（英文版）

基　　金：Project supported by the National Basic Research Program of China(Grant No.2013CB932804);the National Natural Science Foundation of China(Grant Nos.11421063,11647601,11504431,and 21503275);the Scientific Research Foundation of China University of Petroleum(East China)for Young Scholar(Grant Y1304073);financial support through the CAS Biophysics Interdisciplinary Innovation Team Project(Grant No.2060299)

摘　　要：Nanostructures self-assembled by cross-β peptides with ordered structures and advantageous mechanical properties have many potential applications in biomaterials and nanotechnologies. Quantifying the intra-and inter-molecular driving forces for peptide self-assembly at the atomistic level is essential for understanding the formation mechanism and nanomechanics of various morphologies of self-assembled peptides. We investigate the thermodynamics of the intra-and inter-sheet structure formations in the self-assembly process of cross-β peptide KⅢIK by means of steered molecular dynamics simulation combined with umbrella sampling. It is found that the mechanical properties of the intra-and inter-sheet structures are highly anisotropic with their intermolecular bond stiffness at the temperature of 300 K being 5.58 N/m and 0.32 N/m, respectively. This mechanical anisotropy comes from the fact that the intra-sheet structure is stabilized by enthalpy but the inter-sheet structure is stabilized by entropy. Moreover, the formation process of KⅢIK intra-sheet structure is cooperatively driven by the van der Waals （VDW） interaction between the hydrophobic side chains and the electrostatic interaction between the hydrophilic backbones, but that of the inter-sheet structure is primarily driven by the VDW interaction between the hydrophobic side chains. Although only peptide KⅢIK is studied, the qualitative conclusions on the formation mechanism should also apply to other cross-β peptides.Nanostructures self-assembled by cross-β peptides with ordered structures and advantageous mechanical properties have many potential applications in biomaterials and nanotechnologies. Quantifying the intra-and inter-molecular driving forces for peptide self-assembly at the atomistic level is essential for understanding the formation mechanism and nanomechanics of various morphologies of self-assembled peptides. We investigate the thermodynamics of the intra-and inter-sheet structure formations in the self-assembly process of cross-β peptide KⅢIK by means of steered molecular dynamics simulation combined with umbrella sampling. It is found that the mechanical properties of the intra-and inter-sheet structures are highly anisotropic with their intermolecular bond stiffness at the temperature of 300 K being 5.58 N/m and 0.32 N/m, respectively. This mechanical anisotropy comes from the fact that the intra-sheet structure is stabilized by enthalpy but the inter-sheet structure is stabilized by entropy. Moreover, the formation process of KⅢIK intra-sheet structure is cooperatively driven by the van der Waals （VDW） interaction between the hydrophobic side chains and the electrostatic interaction between the hydrophilic backbones, but that of the inter-sheet structure is primarily driven by the VDW interaction between the hydrophobic side chains. Although only peptide KⅢIK is studied, the qualitative conclusions on the formation mechanism should also apply to other cross-β peptides.

关 键 词：molecular dynamics simulation peptide self-assembly intermolecular force THERMODYNAMICS 

分 类 号：O629.72[理学—有机化学]