A1 Refereed original research article in a scientific journal
SITE-SPECIFIC MUTATIONS IN THE D1-POLYPEPTIDE AFFECT THE SUSCEPTIBILITY OF SYNECHOCYSTIS-6803 CELLS TO PHOTOINHIBITION
Authors: MAENPAA P, KALLIO T, MULO P, SALIH G, ARO EM, TYYSTJARVI E, JANSSON C
Publisher: KLUWER ACADEMIC PUBL
Publication year: 1993
Journal: Plant Molecular Biology
Journal name in source: PLANT MOLECULAR BIOLOGY
Journal acronym: PLANT MOL BIOL
Volume: 22
Issue: 1
First page : 1
Last page: 12
Number of pages: 12
ISSN: 0167-4412
DOI: https://doi.org/10.1007/BF00038991
Abstract
Photoinhibition of photosystem II in the cyanobacterium Synechocystis 6803 was followed after site-specific mutagenesis of the DI polypeptide. Mutations were created in the stromal/cytosolic loop connecting helices D and E. Two mutations E243K and CA1, a deletion of the three glutamates 242-244 and a substitution Q241H, were made in the putative cleavage area of the Dl polypeptide. A third mutation E229D was made in the PEST-like sequence. Mutants and control cells were illuminated and F(V)/F(M) was recorded. Compared to the control, the mutants were less photoinhibited. Fluorescence relaxation after a single flash was delayed in CA1. Restoration of F(V)/F(M) after photoinhibition in the mutants was totally dependent on protein synthesis while control cells were able to recover partially also when protein synthesis was inhibited. In addition, the protein synthesis-dependent recovery of CA1 was slowed down. Our results indicate a correlation between the mutated amino acids and photoinhibition of photosystem II.
Photoinhibition of photosystem II in the cyanobacterium Synechocystis 6803 was followed after site-specific mutagenesis of the DI polypeptide. Mutations were created in the stromal/cytosolic loop connecting helices D and E. Two mutations E243K and CA1, a deletion of the three glutamates 242-244 and a substitution Q241H, were made in the putative cleavage area of the Dl polypeptide. A third mutation E229D was made in the PEST-like sequence. Mutants and control cells were illuminated and F(V)/F(M) was recorded. Compared to the control, the mutants were less photoinhibited. Fluorescence relaxation after a single flash was delayed in CA1. Restoration of F(V)/F(M) after photoinhibition in the mutants was totally dependent on protein synthesis while control cells were able to recover partially also when protein synthesis was inhibited. In addition, the protein synthesis-dependent recovery of CA1 was slowed down. Our results indicate a correlation between the mutated amino acids and photoinhibition of photosystem II.
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