Spectral and kinetic evidence for two early electron acceptors in photosystem I
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چکیده
منابع مشابه
Spectral and kinetic evidence for two early electron acceptors in photosystem I.
Triton-fractionated photosystem-I particles poised at -625 mV, where the two bound iron-sulfur proteins are reduced, have been studied by optical and electron paramagnetic resonance spectroscopies from 293 to 5 K. At 5-9 K, these particles exhibit two decay components with lifetimes of 1.3 and 130 msec in the laser pulse-induced absorption and electron paramagnetic resonance signal changes. Spe...
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Steady-state kinetic analyses of the Photosystem II activity elicited by quinones and quinonediimines in KCN/Hg-inhibited chloroplasts reveal that: 1. Quinones generate a single reaction in which one quinone competes with another for photoreduction by Photosystem II. 2. Quinonediimines also compete with one another for photoreduction, but the electron transport activity elicited by quinonediimi...
متن کاملEvidence for two active branches for electron transfer in photosystem I.
All photosynthetic reaction centers share a common structural theme. Two related, integral membrane polypeptides sequester electron transfer cofactors into two quasi-symmetrical branches, each of which incorporates a quinone. In type II reaction centers [photosystem (PS) II and proteobacterial reaction centers], electron transfer proceeds down only one of the branches, and the mobile quinone on...
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Plant-type ferredoxins in Arabidopsis transfer electrons from the photosystem I to multiple redox-driven enzymes involved in the assimilation of carbon, nitrogen, and sulfur. Leaf-type ferredoxins also modulate the switch between the linear and cyclic electron routes of the photosystems. Recently, two novel ferredoxin homologs with extra C-termini were identified in the Arabidopsis genome (AtFd...
متن کاملLaser flash absorption spectroscopy study of ferredoxin reduction by photosystem I: spectral and kinetic evidence for the existence of several photosystem I-ferredoxin complexes.
The existence of three first-order phases has been previously reported for the reduction of soluble ferredoxin by photosystem I (PSI), both from the cyanobacterium Synechocystis sp. PCC 6803 (at pH 8 and in the presence of salts) [Sétif, P. Q. Y., & Bottin, H. (1994) Biochemistry 33, 8495-8504]. The spectra of these three phases (t1/2 < 1 microsecond, = 13-20 and 103-123 microseconds) have been...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1979
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.76.2.770