Propagation of water density changes around a photoperturbed allosteric protein

The movie shows by density difference isocontours the propagation of an allosteric response to an external trigger, here the photo-induced isomerization of an azobenzene linker. These data are from molecular dynamics simulations where the isomerization is taken as instantaneous. The time passed since the isomerization event is indicated on the lower left. The linker is shown in yellow with the rest of the protein in gray (Cartoon). Red isocontours correspond to increased density and blue isocontours correspond to decreased density. The contour surfaces correspond to changes of ±0.01 water/Å3. For comparison, the bulk water density is 0.033 water/Å3.