Finite element simulation of the gating mechanism of mechanosensitive ion channels

In order to eliminate limitations of existing experimental or computational methods (such as patch-clamp technique and molecular dynamics analysis, respectively) a finite element (FE) model for multi length-scale and time-scale investigation of the gating mechanism of mechanosensitive (MS) ion channels has been established. Gating force value (from typical patch clamping values) needed to activate prokaryotic MS ion channels was applied as tensional force to the FE model of the lipid bilayer. Making use of the FE results, we have discussed the effects of the geometrical and the material properties of the Escherichia coli MscL mechanosensitive ion channel in relation to the Young's modulus of the lipid bilayer, which will vary depending on the properties of the cell membrane or cholesterol content in an artificial membrane surrounding the MscL channel. In this study, the FE model shows that when the cell membrane stiffens the required channel activation force considerably increases. This is in agreement with experimental results reported in the literature. In addition, the present study quantifies the relationship between the membrane stress distribution around a 'hole' in the membrane for modeling purposes and the stress concentration in the places where transmembrane proteins are attached to the hole by applying an appropriate mesh refinement as well as defining contact condition in these areas.