Probing the binding sites of exchanged chlorophyll a in LH2 by Raman and site-selection fluorescence spectroscopies.
In this work we have selectively released the 800 nm absorbing bacteriochlorophyll a molecules of the LH2 protein from the photosynthetic bacterium Rhodopseudomonas acidophila, strain 10050, and replaced them with chlorophyll a (Chla). A combination of low-temperature electronic absorption, resonance Raman and site-selection fluorescence spectroscopies revealed that the Chla pigments are indeed bound in the B800 binding site; this is the first work that formally proves that such non-native chlorins can be inserted correctly into LH2.
Laboratoire Lèon Brillouin (CEA-CNRS), CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France. agall@cea.fr
A
A
Gall
B
B
Robert
R J
RJ
Cogdell
M C
MC
Bellissent-Funel
N J
NJ
Fraser
D001426:Bacterial Proteins; D001665:Binding Sites; D002734:Chlorophyll / Q000737:chemistry*; D000077194:Chlorophyll A; D003080:Cold Temperature; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D011485:Protein Binding; D012241:Rhodopseudomonas / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013059:Spectrum Analysis, Raman
C081521:B800-850 light-harvesting complex, bacteria; D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll; D000077194:Chlorophyll A