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Pulling out a peptide chain from β-sheet crystallite： Propagation of instability of H-bonds under shear force

ISSN号：0567-7718
期刊名称：《力学学报：英文版》
时间：0
分类：TG333.21[金属学及工艺—金属压力加工] TB383[一般工业技术—材料科学与工程]
作者机构：[1]Biomechanics and Biomaterials Laboratory, Departmentof Applied Mechanics, Beijing Institute of Technology,Beijing 100081, China, [2]Institute of High Performance Computing, A＊STAR,Singapore 138632, Singapore, [3]CSIRO - Computational Informatics and Digital ProductivityFlagship, Private Bag 10, Clayton South 3169, Australia
相关基金：Acknowledgments The project was supported by the National Science Foundation of China （Grants 11025208, 11372042, 11221202, and 11202026）. We also thank the generous allocation of computing materials by Australian NCI supercomputers. MSL acknowledges the support from CSIRO - Intelligent Processing TCP, CAFHS＇ Capability Development Fund, and CSIRO - Advanced Materials TCP.

作者： Changjian Xu, Dechang Li, Yuan Cheng, Ming Liu, Yongwei Zhang, Baohua Ji

关键词：微晶板材, 不稳定, 氢键, 肽链, 传播, 剪切力, 分子动力学模拟, 机械性能, Silk fibroin , β-Sheet crystallite - H-bondnetwork, Molecular biomechanics, Steered moleculardynamics

中文摘要：

Anti-parallel β-sheet crystallite as the main component of silk fibroin has attracted much attention due to its superior mechanical properties. In this study, we examine the processes of pulling a peptide chain from β-sheet crystallite using steered molecular dynamics simulations to investigate the rupture behavior of the crystallite. We show that the failure of β-sheet crystallite was accompanied by a propagation of instability of hydrogen-bonds(H-bonds) in the crystallite. In addition, we find that there is an optimum size of the crystallite at which the H-bonds can work cooperatively to achieve the highest shear strength. In addition, we find that the stiffness of loading device and the loading rates have significant effects on the rupture behavior of β-sheet crystallite.The stiff loading device facilitates the rebinding of the Hbond network in the stick-slip motion between the chains,while the soft one suppresses it. Moreover, the rupture force of β-sheet crystallites decreases with loading rate. Particularly, when the loading rate decreases to a critical value, the rupture force of the β-sheet crystallite becomes independent of the loading rates. This study provides atomistic details of rupture behaviors of β-sheet crystallite, and, therefore, sheds valuable light on the underlying mechanism of the superior mechanical properties of silk fibroin.

英文摘要：

Anti-parallel β-sheet crystallite as the main component of silk fibroin has attracted much attention due to its superior mechanical properties. In this study, we examine the processes of pulling a peptide chain from β-sheet crystallite using steered molecular dynamics simulations to investigate the rupture behavior of the crystallite. We show that the failure of β-sheet crystallite was accompanied by a propagation of instability of hydrogen-bonds （H-bonds） in the crystallite. In addition, we find that there is an optimum size of the crystallite at which the H-bonds can work cooperatively to achieve the highest shear strength. In addition, we find that the stiffness of loading device and the loading rates have significant effects on the rupture behavior of β-sheet crystallite. The stiff loading device facilitates the rebinding of the Hbond network in the stick-slip motion between the chains, while the soft one suppresses it. Moreover, the rupture force of β-sheet crystallites decreases with loading rate. Particularly, when the loading rate decreases to a critical value, the rupture force of the β-sheet crystallite becomes independent of the loading rates. This study provides atomistic details of rupture behaviors of β-sheet crystallite, and, therefore, sheds valuable light on the underlying mechanism of the superior mechanical properties of silk fibroin.