Spectroscopy on individual light-harvesting 1 complexes of Rhodopseudomonas acidophila.
In this paper the fluorescence-excitation spectra of individual LH1-RC complexes (Rhodopseudomonas acidophila) at 1.2 K are presented. All spectra show a limited number of broad bands with a characteristic polarization behavior, indicating that the excitations are delocalized over a large number of pigments. A significant variation in the number of bands, their bandwidths, and polarization behavior is observed. Only 30% of the spectra carry a clear signature of delocalized excited states of a circular structure of the pigments. The large spectral variety suggests that besides site heterogeneity also structural heterogeneity determines the optical spectrum of the individual LH1-RC complexes. Further research should reveal if such heterogeneity is a native property of the complex or induced during the experimental procedures.
Department of Biophysics, Huygens Laboratory, Leiden University, 2300 RA Leiden, The Netherlands.
Martijn
M
Ketelaars
Clemens
C
Hofmann
Jürgen
J
Köhler
Tina D
TD
Howard
Richard J
RJ
Cogdell
Jan
J
Schmidt
Thijs J
TJ
Aartsma
D001426:Bacterial Proteins; D055592:Biophysical Phenomena; D001703:Biophysics; D045342:Light-Harvesting Protein Complexes; D008051:Lipid Bilayers; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000648:ultrastructure; D011487:Protein Conformation; D012241:Rhodopseudomonas / Q000378:metabolism* / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence / Q000379:methods
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D008051:Lipid Bilayers; D045322:Photosynthetic Reaction Center Complex Proteins; C094744:light-harvesting complex 1, Rhodospirillum