Abstract
The pigment-protein complex, B820, isolated from the long-wavelength antenna (LH-1) of the photosynthetic purple bacterium Rhodospirillum rubrum was studied with polarized nanosecond laser spectroscopy. The polarized triplet (T)-singlet (S) spectrum was obtained at 77 K. The spectrum is significantly different from the T-S spectrum of monomeric BChl a, and can be explained by assuming that upon excitation the absorption band at 825 nm, which is due to a dimeric pair of BChl a molecules, disappears from the absorption spectrum, and is replaced by a monomer absorption band peaking at 809 nm. From the energy-dependence of the triplet yield, the high polarization of the bleaching, and the absence of singlet-triplet quenching we conclude that the B820 complex contains only one dimer of interacting BChl a molecules.
Original language | English (US) |
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Pages (from-to) | 111-119 |
Number of pages | 9 |
Journal | BBA - Bioenergetics |
Volume | 1059 |
Issue number | 1 |
DOIs | |
State | Published - Aug 2 1991 |
Externally published | Yes |
Funding
This work was supported by the Netherlands Organization for Pure Research via the Dutch Foundation for Biophysics and by EEC Grant No. SC1-0004-C. The technical assistance of Mr. W. Spierdijk is gratefully acknowledged.
Keywords
- Bacteriochlorophyll
- Exciton interaction
- Photosynthesis
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology