CD spectroscopy provides evidence for excitonic interactions involving red-shifted chlorophyll forms in photosystem I.
Selective destruction of the strongly dichroic red-shifted chlorophyll form (C709 nm) in photosystem I (PSI) trimers from Spirulina, by either non-selective high intensity illumination (photobleaching) or incubation with low concentrations of Triton X-100 is accompanied by changes in the circular dichroism spectrum of the same amplitude and of opposite sign at 677 nm. The data are interpreted in terms of a dimeric chlorophyll structure with excitonic bands at these two wavelengths. Similar photobleaching experiments with PSI-200 from maize also suggest the presence of bulk antenna/red form excitonic interactions.
Engelmann
E
E
Centro C.N.R. Biologia Cellulare e Molecolare delle Piante, Dipartimento di Biologia, Università di Milano, Italy.
Tagliabue
T
T
Karapetyan
N V
NV
Garlaschi
F M
FM
Zucchelli
G
G
Jennings
R C
RC
D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D003116:Color; D000458:Cyanobacteria / Q000737:chemistry*; D019281:Dimerization; D008027:Light; D045342:Light-Harvesting Protein Complexes; D017830:Octoxynol / Q000494:pharmacology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism*; D045331:Photosystem I Protein Complex; D011485:Protein Binding / Q000187:drug effects / Q000528:radiation effects; D003313:Zea mays / Q000737:chemistry
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D002734:Chlorophyll; D017830:Octoxynol