Fig. 2
The time evolution of an MD trajectory shows that occlusion of the groove is triggered by lipid tail insertion. a Projection (large colored dots) of the 15µs-long WT6 MD trajectory calculated for one of the nhTMEM6 subunits on the 2D tICA landscape from Fig. 1. The colors of the large dots indicate the time-frames in the evolution of the trajectory: darker colors (blue, cyan) are indicating the initial stages of the simulation, lighter colors dots (yellow, green) correspond to the middle part of the trajectory, and red shades show the last third of the trajectory. In this representative trajectory the system is seen to have evolved from microstates 1 to 4, and to 3. b The evolution of the Cα-Cα distance between residues V337 and V447 as a function of time in the WT6 trajectory. c Time evolution of the minimum distance between the lipid tail penetrating the groove and residues V337 (in red) and V447 (in blue). d Structures of representative snapshots showing the gradual occlusion of the groove in going from microstate 1 to 4 and to 3. The color code in (d) is the same as in Fig. 1a; TM4 and TM6 are labeled. Note that the lipid tail present inside the groove in microstate 4 is absent in the ensemble of states in microstate 3, suggesting that once the occluding configuration was established, the lipid tail is no longer necessary for its relative stability
