The rate constant of photoinhibition in vitro is independent of the antenna size of Photosystem II but depends on temperature
- 29 July 1994
- journal article
- Published by Elsevier BV in Biochimica et Biophysica Acta (BBA) - Bioenergetics
- Vol. 1186 (3), 177-185
- https://doi.org/10.1016/0005-2728(94)90177-5
Abstract
Photoinhibition of Photosystem (PS) II was studied in thylakoid membranes, inside-out and rightside-out thylakoid vesicles derived from appressed and non-appressed membrane regions, respectively, in detergent fractionated PS II membranes and in oxygen evolving PS II core complexes. The preparations were illuminated without added electron acceptors, and care was taken to keep the oxidizing side of PS II in a functional condition during the experiments. The first-order rate constant of photoinhibition, measured under given photon flux density, was similar in all preparations derived from appressed thylakoid regions and independent of the antenna size. This antenna size independence indicates that under photoinhibitory conditions in vitro, when most PS II traps are closed, the probability of finding an exciton in the reaction centre is not much larger than the probability of finding it in the antenna. Spillover of excitation energy from PS II to PS I may be an important factor protecting the PS IIβ of stroma thylakoids from photoinhibition. Photoinhibition in vitro is a first-order reaction even at low temperatures where the degradation of the D1 protein is slow, which demonstrates that the photoinhibited PS II centres do not protect the remaining active ones from photoinhibition, at least not in vitro. The activation energy of photoinhibition in pumpkin thylakoids, as measured between 6 and 25°C, was 15 kJ/mol; the rate constant of photoinhibition in pumpkin thylakoids increased both below 6 and above 25°C.Keywords
This publication has 39 references indexed in Scilit:
- MULTIFREQUENCY CROSS‐CORRELATION PHASE FLUOROMETRY OF CHLOROPHYLL a FLUORESCENCE IN THYLAKOID AND PSII‐ENRICHED MEMBRANESPhotochemistry and Photobiology, 1993
- Photoinhibition of hydroxylamine-extracted photosystem II membranes: studies of the mechanismBiochemistry, 1992
- In vitro studies on light-induced inhibition of Photosystem II and D1-protein degradation at low temperaturesBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1990
- Protection from photoinhibition by low temperature in Synechocystis 6714 and in Chlamydomonas reinhardtii: detection of an intermediary stateBiochemistry, 1990
- Photosystem II disorganization and manganese release after photoinhibition of isolated spinach thylakoid membranesFEBS Letters, 1988
- Difference in sensitivity to photoinhibition between photosystem II in the appressed and non-appressed thylakoid regionsFEBS Letters, 1987
- On the role of the QB protein of PS II in photoinhibitionFEBS Letters, 1986
- Inside-out membrane vesicles isolated from spinach thylakoidsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1978
- Chlorophyll—protein complexes of spinach and barley thylakoidsFEBS Letters, 1978
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970