Figure 2
Electrochemically induced near-IR difference spectra of P840 (A) and Nernst plots of its redox reaction (B) in the wild-type (green line), the L688C (red line) and the V689C (blue line) RCs at 297 K.
(A) P840 was oxidized by setting the working electrode at +400 mV and was subsequently reduced at −50 mV in the OTTLE cell. The inset shows expanded spectra in the region of 750–900 nm. (B) The mole fraction of P840+, which was calculated from the difference absorption changes at the positive peak around 1170 nm in the near-infrared difference spectra, was plotted against potentials of the working electrode. Numerical numbers with arrows represent the empirical Em values estimated from least-squares fitting of the plots with theoretical Nernst curves (colored dashed lines) for one-electron redox reactions.
