Abstract– Infrared difference spectra with 4 cm−1 spectral resolution and 10‐u.s temporal resolution, obtained previously with a stroboscopic Fourier‐transform difference technique (Braiman et al., 1991, Proc. Natl. Acad. Sci. USA 88, 2388), were analyzed by means of a global exponential fitting procedure based on singular value decomposition. Using a simple linear kinetic model K → L → M for the bacteriorhodopsin (bR) photocycle in the time range10–1000 μ.s at 16.5°C, it was possible to generate bR → L and bR → M difference spectra with signal/noise ratios comparable to those obtainable with low temperature difference spectroscopy. The resulting time‐resolved bR → L and bR‐→ M difference spectra are both very similar to the corresponding static FTIR difference spectra obtained at 175 K and 250 K, respectively. In the bR → L spectrum, however, there are interesting differences that may indicate a greater degree of deprotonation of Asp‐96 when L is formed at physiological temperatures than when it is observed in a low‐temperature steady state.
|Original language||English (US)|
|Number of pages||6|
|Journal||Photochemistry and photobiology|
|State||Published - Dec 1991|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry