High-precision determination of quantum yields of photoelectric excitation conversion in reaction centers of purple bacteria Rhodospirillum rubrum and Rhodobacter sphaeroides R-26

Abstract

Using an original model of primary events in bacterial photosynthetic reaction centers (RCs), a complete set of kinetic and energy characteristics, and temperature dependences of nanosecond luminescence component(s) emitted by the RCs, upper limits to the quantum yield of primary transmembrane charge separation in RCs of the purple bacterium Rhodospirillum rubrum and the carotenoidless mutant Rhodobacter sphaeroides R-26 have been estimated. The calculations have given the values of 0.915 ± 0.045 and 0.978 ± 0.006, respectively. In the case of Rb. sphaeroides R-26, the quantum yield partly overlapped with that reported earlier (1.02 ± 0.04) by Wraight and Clayton (BBA, 1974. vol. 333, pp. 246–260).