Effect of specific extrinsic polypeptide release on delayed light emission and oxygen evolving patterns in photosystem 2 particles
1991
Maslenkova, L. | Angelova, O. | Zanev, Yu. (Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Fiziologiya na Rasteniyata) | Kurbanova, I. | Kyurdov, B. | Ghadgieva, R. | Dadasheva, S. | Gasanov, R.
The kinetics of flash-induced oxygen evolution and delayed light emission (DLE) were investigated in oxygen evolving photosystem 2 (PS2) particles, depleted of the peripheral membrane proteins of water oxidizing system. In the preparations depleted of the 24x1000 and 16x1000 polypeptides by washing with 1 M NaCl, approximately 55 % of the centres were still operative and no significant changes in either the misses and double hits parameters, S-state turnover time and stability of the centres were observed. DLE kinetics confirmed that the PS2 donor side was not affected. Urea plus NaCl washing released the 33x1000 peripheral protein in parallel with significant changes in DLE kinetics, reflecting an inhibition on the PS2 donor side and a delayed recombination of separated P+680Q- charges. The depleted membranes showed a considerable depression of the O2 flash yields. The biphasic kinetics of the deactivation reactions of the S2 and S3 oxidized states were delayed (the absence of the 33x1000 protein increases the stability of the states). The 33x1000 polypeptide is essential for preservation of the oxygen evolving capacity of the PS2 complexes.
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