Journal article

Publication year: 2005

Pages: 6683-6690

Journal: Journal of Bacteriology

Volume number: 187

Issue number: 19

ISSN: 0021-9193

eISSN: 1098-5530

Open access status: Green

DOI Link: https://doi.org/10.1128/JB.187.19.6683-6690.2005

Publisher: American Society for Microbiology

Abstract: 
Signal transduction protein P, is dephosphorylated in Synechocystis sp. strain PCC 6803 by protein phosphatase PphA. To determine the impact of PphA-mediated P-II dephosphorylation on physiology, the phenotype of a PphA-deficient mutant was analyzed. Mutants lacking either PphA or P-II were impaired in efficient utilization of nitrate as the nitrogen source. Under conditions of limiting photosystem I (PSI)-reduced ferredoxin, excess reduction of nitrate along with impaired reduction of nitrite occurred in P-II signaling mutants, resulting in excretion of nitrite to the medium. This effect could be reversed by increasing the level of PSI-reduced ferredoxin. We present evidence that nonphosphorylated P-II controls the utilization of nitrate in response to low light intensity by tuning down nitrate uptake to meet the actual reduction capacity. This control mechanism can be bypassed by exposing cells to excess levels of nitrate. Uncontrolled nitrate uptake leads to light-dependent nitrite excretion even in wild-type cells, confirming that nitrate uptake controls nitrate utilization in response to limiting photon flux densities.

Harvard Citation style: Kloft, N. and Forchhammer, K. (2005) Signal transduction protein P_II phosphatase PphA is required for light-dependent control of nitrate utilization in Synechocystis sp strain PCC 6803, Journal of Bacteriology, 187(19), pp. 6683-6690. https://doi.org/10.1128/JB.187.19.6683-6690.2005

APA Citation style: Kloft, N., & Forchhammer, K. (2005). Signal transduction protein P_II phosphatase PphA is required for light-dependent control of nitrate utilization in Synechocystis sp strain PCC 6803. Journal of Bacteriology. 187(19), 6683-6690. https://doi.org/10.1128/JB.187.19.6683-6690.2005