Charge separation kinetics in isolated photosynthetic reaction centers of Chloroflexus aurantiacus (with QA reduced) at low temperatures
✍ Scribed by Gerd Schweitzer; Mathias Hucke; Kai Griebenow; Marc G. Müller; Alfred R. Holzwarth
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 515 KB
- Volume
- 190
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
The picosecond fluorescence kinetics of closed (quinone acceptor QA reduced) reaction centers isolated from the phototrophic bacterium ChloroJlexus aurantiacus shows time constants of 220 and z 300 ps (amplitude ratio = 1: I), which are nearly independent of temperature (7 to 80 K). Assuming a three-state kinetic model, we tested various assignments of the kinetics to the electron transfer processes. Only two of these assignments seem to be physically reasonable. One of these includes a fast reversible electron transfer between P and Hu, the pheophytin(s) in the M branch of the reaction center which up to now has been considered virtually inactive in electron transfer. The other possible model involves the formation of a monomeric bacteriochlorophyll anion.