Fig. 3.

Flash-induced absorption changes of WT BR with (blue) and without (red) HtrII (Upper) and BR mutant P200T/V210Y with (blue) and without (red) HtrII (Lower). Scale in absorption units (ordinate) and time (abscissa). Note the 20-fold difference in the time scales. The M intermediate is monitored by 410 nm and the unphotolysed state is monitored by 570 nm. Flash photolysis data were acquired from membrane samples in 4 M NaCl at pH 7.0 in transformants of H. salinarum strain Pho81Wr⁻, which lacks rhodopsins and the transducer proteins HtrI and HtrII.