Gating and inactivation of mechanosensitive channels of small conductance : A continuum mechanics study

Liangliang ZHU, Qiang CUI, Hang XIAO, Xiangbiao LIAO, Xi CHEN*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

2 Citations (Scopus)


Mechanosensitive channels of small conductance (MscS) in Escherichia coli (E. coli) serve as a paradigm for understanding the gating behaviors of the MscS family of ion channels. In this work, we develop a continuum mechanics framework to explore the conformational states of MscS during the gating transition. A complete gating transition trajectory from the closed to the open state along with partially open intermediates is obtained, and the open structure is close to the available structural model from crystallographic studies. The computational efficiency of the modeling framework makes it possible to explore the roles of various structural elements (e.g., loops that connect transmembrane helices) and specific interactions in the gating transition. It is observed that removing either the Asp62-Arg131 salt bridge or the Phe68-Leu111 non-polar interaction leads to essentially non-conducting structures even with a membrane tension close to the lysis limit. The loop connecting TM2 (the second transmembrane helix) and TM3 is found to be essential for force transmission during gating, while the loop connecting TM1 and TM2 does not make any major contribution. Based on the different structural evolutions observed when the TM3 kink is treated as a loop or a helical segment, we propose that the helical propensity of the kink plays a central role in inactivation; i.e., under prolonged sub-threshold membrane tension, transition of the initially flexible loop to a helical segment in TM3 may lead to MscS inactivation. Finally, the gating transition of MscS under different transmembrane voltages is explored and found to be essentially voltage independent. Collectively, results from the current continuum mechanics analysis provide further insights into the gating transition of MscS at structural and physical levels, and specific predictions are proposed for further experimental investigations. © 2018 Elsevier Ltd
Original languageEnglish
Pages (from-to)502-514
Number of pages13
JournalJournal of the Mechanical Behavior of Biomedical Materials
Early online date2 Nov 2018
Publication statusPublished - Feb 2019
Externally publishedYes

Bibliographical note

X. C. acknowledges support from the National Natural Science Foundation of China (China, 11572238 and 11872302), Key R & D Program of Shaanxi (China, 2018ZDXM-GY-131), and Yonghong Zhang Family Center for Advanced Materials for Energy and Environment (United States).


  • Continuum mechanics
  • Gating mechanism
  • Inactivation
  • Mechanobiology
  • Mechanosensitive channel of small conductance


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