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Updated: Oct 18, 2026

Spectrophotometric Determination of Phycobiliprotein Content in Cyanobacterium Synechocystis
Published on: September 11, 2018
Protein PII regulates both inorganic carbon and nitrate uptake and is modified by a redox signal in synechocystis PCC
M Hisbergues1, R Jeanjean, F Joset
1Laboratoire de Chimie Bactérienne, CNRS, 31 Chemin J. Aiguier, 13402, Marseille, France.
Abstract:
In Synechocystis PCC 6803 as in other cyanobacteria, involvement of protein PII in the co-regulation of inorganic carbon and nitrogen metabolism was established based on post-translational modifications of the protein resulting from changes in the carbon/nitrogen regimes. Uptake of bicarbonate and nitrate in response to changes of the carbon and/or nitrogen regimes is altered in a PII-null mutant, indicating that both processes are under control of PII. Modulation of electron flow by addition of methyl viologen with or without duroquinol, or in a NAD(P)H dehydrogenase-deficient mutant, affects the phosphorylation level of PII. The redox state of the cells would thus act as a trigger for PII phosphorylation.
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