Rapidly reversible flash‐induced electron transfer in a P‐700 chlorophyll—protein complex isolated with SDS

Thylakoid Polypeptides of Light and Dark Aged Chloroplasts

“…CPI disappearance seems to be correlated with the decay of PSI activity which indicates that the problem is directly related to disintegration of the Chl-protein complex believed to carry the reaction center of PSI (19). Our results agree with the idea that the 60 kD polypeptide comes from the CPI complex (1,16).…”

Spectral characterization of the intermediate electron acceptor (A1) of photosystem I

“…Kinetic studies at a slower response time have shown a biphasic decay, the slower component having a half-time of -0.5 ms under these conditions. The kinetic response at 430 nm of the preparation heated at 60°C for 5 min is shown in fig.lB, and a rapid decay of the lightinduced absorbance decrease is observed: the halftime of -7 ps is comparable to that observed in [2,10] for conditions where this reaction represents the A; + P700' back-reaction. The spectra of the flash-induced aA in the region from 350-550 nm are shown in fig2.…”

“…Shuvalov et al [5] used strongly reducing conditions where secondary electron acceptors, such as the bound ironsulfur centers, are reduced prior to illumination while a different approach has been to use an electrophoretitally isolated photosystem I preparation made with the detergent, sodium dodecyl sulfate (SDS) [2,10]; this preparation is devoid of secondary electron acceptors but still contains Al. Here we report a convenient method for the preparation of photosystem I fragments which lack the secondary electron acceptors of photosystem I but retain a functional photosystem I reaction center in that P700 and A1 are present.…”

Chlorophyll-proteins of thylakoids from wild-type and mutants of barley (Hordeum vulgare L.)

“…The antenna chlorophylls in this band do not fluoresce, indicating the presence of an efficient quencher. This is likely to be P700, since it has been shown to be present in the Chla-PI band from tobacco thytakoids (19,26). Conversion of the P700 chlorophylls to pheophytin by acetic acid destroys the quenching ability and the antenna chlorophylls (pheophytins) can then emit red fluorescent light (Figure l c).…”