A1 Refereed original research article in a scientific journal
LIGHT-DEPENDENT PHOSPHORYLATION OF D1 REACTION-CENTER PROTEIN OF PHOTOSYSTEM-II - HYPOTHESIS FOR THE FUNCTIONAL-ROLE IN-VIVO
Authors: RINTAMAKI E, KETTUNEN R, TYYSTJARVI E, ARO EM
Publisher: MUNKSGAARD INT PUBL LTD
Publication year: 1995
Journal: Physiologia Plantarum
Journal name in source: PHYSIOLOGIA PLANTARUM
Journal acronym: PHYSIOL PLANTARUM
Volume: 93
Issue: 1
First page : 191
Last page: 195
Number of pages: 5
ISSN: 0031-9317
DOI: https://doi.org/10.1034/j.1399-3054.1995.930127.x
Abstract
Reversible phosphorylation of the D1 reaction centre protein of photosystem II (PSII) occurs in thylakoid membranes of higher plants. The significance of D1 protein phosphorylation in the function of PSII is not yet clear. This paper summarizes the data implying that phosphorylation of D1 protein in higher plants is involved in the regulation of the repair cycle of photoinhibited PSII centres. Photoinhibition of PSII, D1 protein phosphorylation and degradation have been studied in vivo in higher plant leaves acclimated to different growth irradiances. It is shown that photoinhibitory illumination induces maximal phosphorylation of the D1 protein. Under these conditions D1 turnover is also saturated. We postulate that phosphorylation retards the degradation of damaged D1 protein under conditions where rapid replacement by a new DI copy is not possible. This would protect PSII from total disassembly and degradation of all PSII subunits. We conclude that the phosphorylation of D1 protein and the regulation of D1 protein degradation may have evolved together. Furthermore, these characteristics seem to be related to the highly organized structure of higher-plant type thylakoid membranes, since the capability to phosphorylate D1 protein is restricted to seed plants.
Reversible phosphorylation of the D1 reaction centre protein of photosystem II (PSII) occurs in thylakoid membranes of higher plants. The significance of D1 protein phosphorylation in the function of PSII is not yet clear. This paper summarizes the data implying that phosphorylation of D1 protein in higher plants is involved in the regulation of the repair cycle of photoinhibited PSII centres. Photoinhibition of PSII, D1 protein phosphorylation and degradation have been studied in vivo in higher plant leaves acclimated to different growth irradiances. It is shown that photoinhibitory illumination induces maximal phosphorylation of the D1 protein. Under these conditions D1 turnover is also saturated. We postulate that phosphorylation retards the degradation of damaged D1 protein under conditions where rapid replacement by a new DI copy is not possible. This would protect PSII from total disassembly and degradation of all PSII subunits. We conclude that the phosphorylation of D1 protein and the regulation of D1 protein degradation may have evolved together. Furthermore, these characteristics seem to be related to the highly organized structure of higher-plant type thylakoid membranes, since the capability to phosphorylate D1 protein is restricted to seed plants.
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