Abstract
Fluorescence of bacteriochlorophylls (BChl) c and a in isolated chlorosomes of Chloroflexus aurantiacus was shown to be controlled by two types of redox-sensitive mechanisms. Fluorescence of the 750 nm Bchl c band decreased as the redox potential of the medium was shifted positive. Aerobic redox titration indicated an apparent Em of 410mV for decrease to 1/5. Decay lifetimes of Bchl c band was decreased from 24 and 480 ps to 9.1 and 227 ps by ferricyanide. The two-step fluorescence quenching is different from the quenching in green sulfur bacterial chlorosomes (1-3) and seems to be evolved in the different growth environments. 1) N V Karapetyan et al. (1980) BBA 593: 254-260.2) J Wang et al. (1990) BBA1015: 457-463. 3) Frigaard et al.(1998) Photosynth.Res 58: 81-90
