MS01-P02 Retinal isomerization in bacteriorhodopsin captured by a femtosecond X-ray laserUltrafast isomerization of retinal is the primary step in photoresponsive biological functions including vision in humans and ion-transport across bacterial membranes. We studied the sub-picosecond structural dynamics of retinal isomerization in the light-driven proton pump bacteriorhodopsin using an X-ray laser. A series of structural snapshots with near-atomic spatial and temporal resolution in the femtosecond regime show how the excited all-trans retinal samples conformational states within the protein binding pocket prior to passing through a twisted geometry and emerging in the 13-cis conformation. Our findings suggest ultrafast collective motions of aspartic acid residues and functional water molecules in the proximity of the retinal Schiff base as a key ingredient for this stereo-selective and effcient photochemical reaction.References:
Nogly, P. et al. Retinal isomerization in bacteriorhodopsin captured by a femtosecond X-ray laser, under revision.
Nango, E. et al. (2016). Science, 354, 1552-1557.
Nogly, P. et al. (2016). Nat. Commun, 7, 12314.Keywords: time-resolved crystallography, X-ray free electron laser, ultra-fast dynamics