ISSN:
1573-5079
Keywords:
bacterial reaction center
;
electron transfer
;
energy transfer
;
monomeric bacteriochlorophyll
;
primary charge separation
;
primary donor
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The efficiency of energy transfer from the monomeric pigments to the primary donor was determined from 77 K steady-state fluorescence excitation spectra of three mutant reaction centers, YM210L, YM210F and LM160H / FM197H. For all three reaction centers this efficiency was not 100% and ranged between 55 and 70%. For the YM210L mutant it was shown using pump-probe spectroscopy with B band excitation at 798 nm that the excitations which are not transferred to P give rise to efficient charge separation. The results can be interpreted with a model in which excitation of the B absorbance band leads to direct formation of the radical pair state BA +H A − in addition to energy transfer to P. It is also possible that some P+BA − is formed from B*. In previous publications we have demonstrated the operation of such alternative pathways for transmembrane electron transfer in a YM210W mutant reaction center [van Brederode et al. (1996) The Reaction center of Photosynthetic Bacteria, pp 225–238; (1997a,b) Chem Phys Lett 268: 143–149; Biochemistry 36: 6855–6861]. The results presented here demonstrate that these alternative mechanisms are not peculiar to the YM210W reaction center.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005925917867
