Figure 1. The tethered NompC channel was opened by compression of the intracellular ankyrin repeat domain.
(A) The simulation systems. The NompC was divided into two subsystems, denoted by the cyan and red rectangular boxes, for the molecular dynamics (MD) simulations. (B−D) The transmembrane (TM) pore size evolution for the force-free (B), pulling/stretch (C), and pushing/compression (D) simulations, calculated from the MD trajectories FI0, SI0, and CI0 (Supplementary file 1a), respectively. (E) A schematic figure of the cell-attached patch-clamp electrophysiological experiment for NompC. (F) Representative traces of the electrophysiological measurements for the S2 blank cell and NompC-expressed cell, showing that there are significantly larger signals under positive pressure (PP) in the presence of NompC. (G) The mean and standard deviation (SD) of the mechano-gated currents in the S2 blank and NompC expressing cells under positive (PP) and negative pressure (NP) in the cell-attached patch-clamp experiments (S2_NP: n = 6; S2_PP: n = 6; NompC_NP: n = 5; NompC_PP: n = 7). All of the error bars denote ± SD.
Figure 1—figure supplement 1. The sequence of NompC used for the molecular dynamics (MD) simulations (highlighted).
Figure 1—figure supplement 2. The transmembrane (TM) pore size evolution of multiple replicate simulations with a slower pulling/pushing speed, for the force-free, pulling/stretch, and pushing/compress simulations, calculated from the molecular dynamics (MD) trajectories FI1-3, SI1-3, and CI1-3 (Supplementary file 1a), respectively.
Figure 1—figure supplement 3. This figure is similar to Figure 1B–D except that the pore radius was calculated with the structure of the transmembrane (TM) backbone (side chain removed) in the molecular dynamics (MD) trajectories FI0, SI0, and CI0 (Supplementary file 1a),respectively.
Figure 1—figure supplement 4. This figure is similar to Figure 1—figure supplement 2 except that the pore radius was calculated with the structure of the transmembrane (TM) backbone only (side chain removed) in the molecular dynamics (MD) trajectories FI1-3, SI1-3, and CI1-3, respectively.
Figure 1—figure supplement 5. The number of water molecules around the gate region of NompC in the molecular dynamics (MD) simulations.
Figure 1—figure supplement 6. Sodium ions spontaneously permeated through the partially opened gate in the ‘pushing’ molecular dynamics (MD) simulations in the absence of a transmembrane potential in the trajectories CI1 and CI2, respectively.
Figure 1—figure supplement 7. Ion density maps from the ion permeation trajectories.
Figure 1—figure supplement 8. The sodium ion and potassium ion permeation count through the partially opened structure of NompC in the permeation molecular dynamics (MD) trajectories PI1-3 and PII1-3, respectively.
Figure 1—figure supplement 9. Experiment results of the inside-out (IO) and outside-out (OO) patch clamp.
Figure 1—figure supplement 10. The mechanosensitive current can be blocked by GdCl3.
Figure 1—figure supplement 11. Distances between the centers of AR29 and the transmembrane (TM) domain of NompC in the 250 ns molecular dynamics/steered molecular dynamics (MD/SMD) simulations of system I, for the free, pulling, and pushing simulations, calculated from the MD trajectories FI0, SI0, and CI0, respectively.
Figure 1—figure supplement 12. Distances between the centers of AR29 and the transmembrane (TM) domain of NompC in the 500 ns molecular dynamics/steered molecular dynamics (MD/SMD) simulations of system I, for the free, pulling, and pushing simulations, calculated from the MD trajectories FI1-3, SI1-3, and CI1-3, respectively.
Figure 1—figure supplement 13. The overlaid initial and 200 ns conformations of the simulation system I in the free, pulling/stretch, and pushing/compress simulations, from the molecular dynamics (MD) trajectories FI0, SI0, and CI0, respectively.
