FUNCTIONING OF OLIGOMERIC-TYPE LIGHT-HARVESTING ANTENNA

In our previous work, we developed, for the first time, a theory of ex citation energy transfer within an oligomeric-type light-harvesting an tenna and, in particular, within the chlorosome of green bacteria (Bio phys.J., 1996, vol.71, pp.995-1010). The theory was recently developed for a new original exciton model of aggregation of chlorosomal pigmen ts, bacteriochlorophylls (BChl) c/d/e (Biochem. Mol. Biol. Int., 1996, vol.40, No.2, pp. 243-252). In this paper, it was demonstrated with p icosecond fluorescence spectroscopy that this theory explains the ante nna-size-dependent kinetics of fluorescence decay in chlorosomal anten na, measured for intact cells of different cultures of the green bacte rium Chlorobium limicola with different chlorosomal antenna size deter mined by electron microscopic examination of the ultrathin sections of the cells. According to our model, the energy transfer dynamics withi n the chlorosome imply the formation of a cylindrical exciton, delocal ized over a tubular aggregate of BChl c chains, anti inductive-resonan ce-type transfer of such a cylindrical exciton between the nearest tub ular BChl c aggregates and to BChl a of the chlorosome.