A1 Refereed original research article in a scientific journal

Substantial deletions in the DE loop of the photosystem II D1 protein do not prevent its turnover or cross-linking with the alpha-subunit of cytochrome b559. A study using Synechocystis sp PCC 6803 mutants




AuthorsBarbato R, Mulo P, Bergo E, Carbonera D, Maenpaa P, Giacometti GM, Barber J, Aro EM

PublisherGUSTAV FISCHER VERLAG

Publication year1999

JournalJournal of Plant Physiology

Journal name in sourceJOURNAL OF PLANT PHYSIOLOGY

Journal acronymJ PLANT PHYSIOL

Volume154

Issue5-6

First page 591

Last page596

Number of pages6

ISSN0176-1617

DOIhttps://doi.org/10.1016/S0176-1617(99)80231-4


Abstract
Light-induced damage of photosystem II brings about the specific degradation of the reaction centre D1-protein. Under similar conditions, cross-linking occurs between this protein and the alpha-subunit of cytochrome b559, giving rise to a 41-kDa adduct. In order to understand whether there is any relationship between the formation of the 41-kDa adduct and the D1-protein degradation, three deletion mutants of Synechocystis sp. PCC 6803 have been employed. The three mutants have deletions in the DE loop of the D1-protein, Delta(G240-V249), Delta(R225-F239) and Delta(R225-V249), which incorporates the < PEST-like > region and the FGQEEET motif. These regions have been implicated in the degradation and turnover of the D1 protein, and also in the formation of the 41-kDa adduct. Using a proteolytic digestion assay we show that the deletions induce conformational changes in the putative helical region of the DE-loop. However, the deletion mutants mantain their abilities to degrade and turnover the D1 protein, and also to generate the 41-kDa adduct, reinforcing the idea of a correlation between the two phenomena.



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