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CD spectroscopy provides evidence for excitonic interactions involving red‐shifted chlorophyll forms in photosystem I
Author(s) -
Engelmann E.,
Tagliabue T.,
Karapetyan N.V.,
Garlaschi F.M.,
Zucchelli G.,
Jennings R.C.
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02533-9
Subject(s) - photobleaching , photosystem i , p700 , photosystem ii , light harvesting complexes of green plants , chemistry , photochemistry , circular dichroism , plastocyanin , spectroscopy , chlorophyll a , far red , chlorophyll , dichroic glass , crystallography , fluorescence , photosynthesis , red light , physics , optics , botany , biology , biochemistry , organic chemistry , quantum mechanics
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.