PRESENCE AND SIGNIFICANCE OF MINOR ANTENNA COMPONENTS IN THE ENERGY-TRANSFER SEQUENCE OF THE GREEN PHOTOSYNTHETIC BACTERIUM CHLOROFLEXUS-AURANTIACUS

Antenna components in the energy transfer processes of a green photosy nthetic bacterium Chloroflexus aurantiacus were spectrally investigate d by time-resolved fluorescence spectroscopy at -196 degrees C on inta ct cells. Besides major antenna components so far reported, three mino r components were resolved; those were Bchl c located at 785 nm, the b aseplate Bchl a at 819 nm and Bchl a in the B808-866 complex al 910 nm . The last component was assigned to a longer wavelength antenna close ly associated with a reaction center. An additional Bchl c fluorescenc e component was kinetically suggested to be present, which can be an e nergy donor to a major Bchl c. Presence of these minor components was signified in terms of (1) increase in the spectral overlap integral an d (2) adjustment of the direction of dipole moments in the energy tran sfer sequence of intact cells.