Acta Mechanica Sinica

, Volume 31, Issue 3, pp 416–424 | Cite as

Pulling out a peptide chain from \({\upbeta }\)-sheet crystallite: Propagation of instability of H-bonds under shear force

  • Changjian Xu
  • Dechang LiEmail author
  • Yuan Cheng
  • Ming Liu
  • Yongwei Zhang
  • Baohua JiEmail author


Anti-parallel \({\upbeta }\)-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 \({\upbeta }\)-sheet crystallite using steered molecular dynamics simulations to investigate the rupture behavior of the crystallite. We show that the failure of \({\upbeta }\)-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 \({\upbeta }\)-sheet crystallite. The stiff loading device facilitates the rebinding of the H-bond network in the stick-slip motion between the chains, while the soft one suppresses it. Moreover, the rupture force of \({\upbeta }\)-sheet crystallites decreases with loading rate. Particularly, when the loading rate decreases to a critical value, the rupture force of the \({\upbeta }\)-sheet crystallite becomes independent of the loading rates. This study provides atomistic details of rupture behaviors of \({\upbeta }\)-sheet crystallite, and, therefore, sheds valuable light on the underlying mechanism of the superior mechanical properties of silk fibroin.


Silk fibroin \({\upbeta }\)-Sheet crystallite H-bond network Molecular biomechanics Steered molecular dynamics 



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.


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Copyright information

© The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Biomechanics and Biomaterials Laboratory, Department of Applied MechanicsBeijing Institute of TechnologyBeijingChina
  2. 2.Institute of High Performance Computing, A*STARSingaporeSingapore
  3. 3.CSIRO - Computational Informatics and Digital Productivity FlagshipClayton SouthAustralia

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