Nanomechanical properties of MscL α helices: A steered molecular dynamics study

Bavi, N ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1080/19336950.2016.1249077
  3. Publisher: Taylor and Francis Inc , 2017
  4. Abstract:
  5. Gating of mechanosensitive (MS) channels is driven by a hierarchical cascade of movements and deformations of transmembrane helices in response to bilayer tension. Determining the intrinsic mechanical properties of the individual transmembrane helices is therefore central to understanding the intricacies of the gating mechanism of MS channels. We used a constant-force steered molecular dynamics (SMD) approach to perform unidirectional pulling tests on all the helices of MscL in M. tuberculosis and E. coli homologs. Using this method, we could overcome the issues encountered with the commonly used constant-velocity SMD simulations, such as low mechanical stability of the helix during stretching and high dependency of the elastic properties on the pulling rate. We estimated Young's moduli of the α-helices of MscL to vary between 0.2 and 12.5 GPa with TM2 helix being the stiffest. We also studied the effect of water on the properties of the pore-lining TM1 helix. In the absence of water, this helix exhibited a much stiffer response. By monitoring the number of hydrogen bonds, it appears that water acts like a ‘lubricant’ (softener) during TM1 helix elongation. These data shed light on another physical aspect underlying hydrophobic gating of MS channels, in particular MscL. © 2017 Taylor & Francis
  6. Keywords:
  7. All-atom simulation ; Constant velocity ; Mechanosensitive channel ; Mycobacterium tuberculosis ; Nanovalve ; Young's modulus ; Lubricating agent ; Membrane protein ; Transmembrane helix 1 ; Unclassified drug ; Water ; Bacterial protein ; Escherichia coli protein ; Ion channel ; MscL protein, E coli ; Tb-MscL protein, Mycobacterium tuberculosis ; Alpha helix ; Article ; Atomic force microscopy ; Channel gating ; Constant force ; Elasticity ; Escherichia coli ; Force ; Hydrogen bond ; Hydrophobicity ; Membrane potential ; Molecular dynamics ; Molecular mechanics ; Molecular stability ; Nonhuman ; Stretching ; Temperature ; Velocity ; X ray crystallography ; Young modulus ; Biomechanics ; Chemistry ; Mechanics ; Metabolism ; Nanotechnology ; Porosity ; Bacterial Proteins ; Biomechanical Phenomena ; Escherichia coli Proteins ; Ion Channels ; Mechanical Phenomena ; Molecular Dynamics Simulation ; Protein Conformation, alpha-Helical
  8. Source: Channels ; Volume 11, Issue 3 , 2017 , Pages 209-223 ; 19336950 (ISSN)
  9. URL: https://www.tandfonline.com/doi/full/10.1080/19336950.2016.1249077#