A photosystem 1 psaFJ-null mutant of the cyanobacterium Synechocystis PCC 6803 expresses the isiAB operon under iron replete conditions.
A psaFJ-null mutant of Synechocystis sp. strain PCC 6803 was characterised. As opposed to similar mutants in chloroplasts of green algae, electron transfer from plastocyanin to photosystem 1 was not affected. Instead, a restraint in full chain photosynthetic electron transfer was correlated to malfunction of photosystem 1 at its stromal side. Our hypothesis is that absence of PsaF causes oxidative stress, which triggers the induction of the 'iron stress inducible' operon isiAB. Products are the IsiA chlorophyll-binding protein (CP43') and the isiB gene product flavodoxin. Supporting evidence was obtained by similar isiAB induction in wild type cells artificially exposed to oxidative stress.
Jeanjean
Robert
R
LCB-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
Zuther
Ellen
E
Yeremenko
Nataliya
N
Havaux
Michel
M
Matthijs
Hans C P
HC
Hagemann
Martin
M
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D000458:Cyanobacteria; D004579:Electron Transport; D005418:Flavodoxin / Q000096:biosynthesis / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007501:Iron / Q000494:pharmacology; D045342:Light-Harvesting Protein Complexes / Q000096:biosynthesis / Q000235:genetics; D009154:Mutation; D009876:Operon / Q000187:drug effects / Q000235:genetics; D018384:Oxidative Stress; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045331:Photosystem I Protein Complex / Q000235:genetics*
D001426:Bacterial Proteins; D005418:Flavodoxin; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; C079742:psaF protein, bacteria; C076726:chlorophyll A binding protein CP43, Cyanobacteria; D007501:Iron