Premium
Nanosecond electron transfer kinetics in photosystem I as obtained from transient EPR at room temperature
Author(s) -
Bock Christian H.,
van der Est Arthur J.,
Brettel Klaus,
Stehlik Dietmar
Publication year - 1989
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 - 10.1016/0014-5793(89)81247-5
Subject(s) - electron paramagnetic resonance , electron transfer , photosystem i , chemistry , photochemistry , electron acceptor , photosynthetic reaction centre , ultrafast laser spectroscopy , p700 , nanosecond , electron transport chain , photosystem ii , microsecond , spectral line , kinetics , pulsed epr , acceptor , analytical chemistry (journal) , photosynthesis , nuclear magnetic resonance , spectroscopy , laser , physics , optics , chromatography , magnetic resonance imaging , condensed matter physics , biochemistry , quantum mechanics , radiology , medicine , spin echo , astronomy
Transient EPR spectra of photosystem I (PS I) in spinach chloroplasts and PS I particles prepared from Synechococcus are presented. Two consecutive spectra are observed after the laser pulse. The decay time of the first spectrum is equal to the rise time of the second spectrum. The two spectra represent sequential charge‐separated states in the electron transfer chain and the time constant of the electron transfer step between them is found to be t 1/e = 260 ± 20 ns for the Synechococcus PS I particles as well as for the spinach chloroplasts. The first spectrum is assigned to the P + 700 A − 1 pair, where A − 1 is the second electron acceptor, probably a quinone‐like molecule. The second spectrum covers the region of the P + 700 signal and may be part of the spectrum due to the coupled radical pair P + 700 (FeS), where (FeS) − is the first iron‐sulfur center along the electron transfer chain.