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Red chlorophyll excitation dynamics in Arthrospira platensis photosystem I trimeric complexes as studied by femtosecond transient absorption spectroscopy
Author(s) -
Kompanets Viktor,
Shubin Vladimir,
Terekhova Irina,
Kotova Elena,
Kozlovsky Vladimir,
Novoderezhkin Vladimir,
Chekalin Sergey,
Karapetyan Navasard,
Razjivin Andrei
Publication year - 2014
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/j.febslet.2014.07.038
Subject(s) - ultrafast laser spectroscopy , femtosecond , photosystem i , picosecond , spectroscopy , absorption (acoustics) , absorption spectroscopy , photochemistry , photosystem ii , chemistry , excitation , chlorophyll a , analytical chemistry (journal) , kinetics , materials science , photosynthesis , optics , laser , physics , quantum mechanics , composite material , biochemistry , chromatography
Femtosecond absorption spectroscopy was applied to study for the first time excitation dynamics in isolated photosystem I trimers from Arthrospira platensis , which display extremely long‐wavelength absorption peaks. Pump–probe spectra observed at 77 K in the timescale of dozens of picoseconds upon 70‐fs excitation revealed two maxima near 710 and 730 nm, which correspond to red chlorophyll forms. Bleaching at 680 nm developed in ∼200 fs, whereas the bleaching kinetics at 710 and 730 nm exhibited two components with time constants of 1 and 5.5 ps. Comparison of the kinetics of bleaching development at 710 nm and 730 nm with that of bleaching decay at 680 nm indicated that both long‐wavelength forms of trimers are populated mainly via direct energy transfer from bulk chlorophyll.