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Phosphoenolpyruvate carboxylase from the cyanobacterium Synechocystis sp. PCC 6803 is under global metabolic control by P II signaling
Author(s) -
Scholl Jörg,
Dengler Lisa,
Bader Laura,
Forchhammer Karl
Publication year - 2020
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14512
Subject(s) - phosphoenolpyruvate carboxylase , biology , biochemistry , synechocystis , phosphoenolpyruvate carboxykinase , enzyme , malic enzyme , metabolic pathway , dehydrogenase , mutant , gene
Phosphoenolpyruvate carboxylase (PEPC) is the second major carbon‐fixing enzyme in photoautotrophic organisms. PEPC is required for the synthesis of amino acids of the glutamate and aspartate family by replenishing the TCA cycle. Furthermore, in cyanobacteria, PEPC, together with malate dehydrogenase and malic enzyme, forms a metabolic shunt for the synthesis of pyruvate from PEP. During this process, CO 2 is first fixed and later released again. Due to its central metabolic position, it is crucial to fully understand the regulation of PEPC. Here, we identify PEPC from the cyanobacterium Synechocystis sp. PCC 6803 (PEPC) as a novel interaction partner for the global signal transduction protein P II . In addition to an extensive characterization of PEPC, we demonstrate specific P II –PEPC complex formation and its enzymatic consequences. PEPC activity is tuned by the metabolite‐sensing properties of P II : Whereas in the absence of P II, PEPC is subjected to ATP inhibition, it is activated beyond its basal activity in the presence of P II . Furthermore, P II –PEPC complex formation is inhibited by ADP and PEPC activation by P II ‐ATP is mitigated in the presence of 2‐OG, linking PEPC regulation to the cell's global carbon/nitrogen status. Finally, physiological relevance of the in vitro measurements was proven by metabolomic analyses of Synechocystis wild‐type and P II ‐deficient cells.