Controlling the pKa of the bacteriorhodopsin Schiff base by use of artificial retinal analogues.

摘要: Artificial bacteriorhodopsin pigments based on synthetic retinal analogues carrying an electron-withdrawing CF3 substituent group were prepared. The effects of the spectra, photocycles, and Schiff base pKa values analyzed. A reduction 5 units in is observed when located at C-13 polyene position, vicinity protonated nitrogen. results lead to unambiguous characterization (direct) titration conclusion that deprotonation rate during photocycle (i.e., generation M412 intermediate) determined by a structural change protein.