Jr. Burie et al., STEP-SCAN FT-IR SPECTROSCOPY OF ELECTRON-TRANSFER IN THE PHOTOSYNTHETIC BACTERIAL REACTION-CENTER, Applied spectroscopy, 47(9), 1993, pp. 1401-1404
Step-scan light-induced FT-IR difference spectra (1800 1200 cm-1) of R
hodobacter sphaeroides photosynthetic bacterial reaction centers at lo
w temperature and with a 10-mus time resolution are presented. The mol
ecular changes and relaxation processes accompanying the photoxidation
of the primary electron donor (P) are already present 10 mus after ex
citation. The photoconversion of P to the triplet state gives rise to
characteristic IR absorption changes which decay with a half-time of 1
30 mus. A negative band at 1695 cm-1 and a positive one at 1670 cm-1 a
re assigned to the 9-keto carbonyl of bacteriochlorophyll in the state
s P and P-3, respectively.