L protein, encoded by psbL, restores normal functioning of the primary quinone acceptor, QA, in isolated D1/D2/CP47/Cytb‐559/I photosystem II reaction center core complex

摘要

>Plastoquinone-9(PQ-9)-depleted PSII reaction center core complex, consisting of CP47/D1/D2/Cytb-55911, was isolated from spinach PSII particles. PQ-9, lipids and several proteins were extracted from the original PSII particles and separated by several steps of chromatography to be reconstituted into the isolated complex. PQ-9 reconstituted in the complex with the help of thylakoid lipids (digalactosyldiglyceride) did not function as Q_A by itself. However, PQ-9 simultaneously reconstituted with L protein and the thylakoid lipids successfully functioned as Q_A in the complex. Other proteins of PSII origin, such as CP43, H, K, nuclear encoded 4.1 and 5.0 kDa proteins, are unable to restore the Q_A activity in the complex.