Figure 2.
M2TM dynamics triggered by a laser-induced pH jump. (a) Time-dependent Trp fluorescence emission signal of a solution containing NPE-sulfate (0.8 mM) and M2TM reconstituted in a DPPC bicelle following a pH jump from pH 8.0 to 6.0, initiated with a 355 nm laser pulse. The data represent an average of 10 laser shots and were fit to a double exponential decay (red curve). (b) Dependence of the rate constant k1 of M2TM as a function of Δ[H+] at 25 °C. The red line is a linear fit to the data. (c) Schematic representation of the proton transfer pathway and proton channel activation process.