Photoelectric response of the N intermediate of bacteriorhodopsin and its mutant T46V.

Double flash experiments were performed in order to gain information about the characteristics of the N intermediates of the photocycle of bacteriorhodopsin. The N intermediates of wild-type bacteriorhodopsin and mutant T46V were excited at different delay times after the first laser flash which induced the photocycle and the electric responses were registered. These electric signals revealed that charge motions occurred in both cases, though charge translocation, i.e. H(+) pumping, could not be observed. The delay time dependence of the electric signals is characterized by two distinct processes corresponding to two substates of the N intermediates.