Mechanosensitive Channel Activation by Diffusio-Osmotic Force

Abstract

For ion channel gating, the appearance of two distinct conformational states and the discrete transitions between them is essential, and therefore of crucial importance to all living organisms. We show that the physical interplay between two structural elements that are commonly present in bacterial mechanosensitive channels, namely a charged vestibule and a hydrophobic constriction, creates two distinct conformational states, open and closed, as well as the gating between them. We solve the nonequilibrium Stokes-Poisson-Nernst-Planck equations, extended to include a molecular potential of mean force, and show that a first order transition between the closed and open states arises naturally from the diffusio-osmotic stress caused by the ions and water inside the channel and the elastic restoring force from the membrane. Our proposed gating mechanism is likely to be important for a broad range of ion channels, as well as for biomimetic channels and ion channel-targeting therapeutics.

References in corpus (8)

• Nanofluidics, from bulk to interfaces
• Optimizing water permeability through the hourglass shape of aquaporins
• The influence of geometry, surface character and flexibility on the permeation of ions and water through biological pores
• Sitting at the edge: How biomolecules use hydrophobicity to tune their interactions and function
• Analytic models for mechanotransduction: gating a mechanosensitive channel
• Intermittent permeation of cylindrical nanopores by water
• Quantized ionic conductance in nanopores
• An improved coarse-grained model of solvation and the hydrophobic effect

Cited by in corpus (6)

• Osmosis, from molecular insights to large-scale applications
• Dramatic pressure-sensitive ion conduction in conical nanopores
• Sustained unidirectional rotation of a self-organized DNA rotor on a nanopore
• Solidification and superlubricity with molecular alkane films
• Mechanical inhibition of dissipation in a thermodynamically consistent active solid
• Topological phase locking in stochastic oscillators