Influence of Cholesterol Concentration on Bacteriorhodopsin Photocycle

The photocycle of the membrane protein bacteriorhodopsin in Dipalmitoylphosphatidylcholine(DPPC)/Cholesterol membranes with various cholesterol concentrations has been studied using the time-resolved spectroscopy method. The temperature dependences of the rate constants of bacteriorhodopsin transitions between transient states are shown to satisfy the Eyring equation. It is proved that the growth of the cholesterol concentration in the DPPC membrane accelerates the bacteriorhodopsin photocycle.