Metabolic Changes in Synechocystis PCC6803 upon Nitrogen-Starvation: Excess NADPH Sustains Polyhydroxybutyrate Accumulation
Autor: | Maximilian Schlebusch, Joachim Kopka, Karl Forchhammer, Jan Hüge, Martin Hagemann, Waldemar Hauf |
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Jazyk: | angličtina |
Rok vydání: | 2013 |
Předmět: |
Cyanobacteria
cyanobacteria metabolome nitrogen starvation sorbitol NADPH/NADP ratio redox balance Polyhydroxybutyrate PHB synthase Endocrinology Diabetes and Metabolism Mutant lcsh:QR1-502 macromolecular substances Biology Biochemistry Article lcsh:Microbiology chemistry.chemical_compound Molecular Biology Synechocystis Wild type technology industry and agriculture Metabolism biology.organism_classification PHB synthase chemistry PHB synthase Sorbitol lipids (amino acids peptides and proteins) Intracellular |
Zdroj: | Metabolites, Vol 3, Iss 1, Pp 101-118 (2013) Metabolites; Volume 3; Issue 1; Pages: 101-118 Metabolites |
ISSN: | 2218-1989 |
Popis: | Polyhydroxybutyrate (PHB) is a common carbon storage polymer among heterotrophic bacteria. It is also accumulated in some photoautotrophic cyanobacteria; however, the knowledge of how PHB accumulation is regulated in this group is limited. PHB synthesis in Synechocystis sp. PCC 6803 is initiated once macronutrients like phosphorus or nitrogen are limiting. We have previously reported a mutation in the gene sll0783 that impairs PHB accumulation in this cyanobacterium upon nitrogen starvation. In this study we present data which explain the observed phenotype. We investigated differences in intracellular localization of PHB synthase, metabolism, and the NADPH pool between wild type and mutant. Localization of PHB synthase was not impaired in the sll0783 mutant; however, metabolome analysis revealed a difference in sorbitol levels, indicating a more oxidizing intracellular environment than in the wild type. We confirmed this by directly measuring the NADPH/NADP ratio and by altering the intracellular redox state of wild type and sll0783 mutant. We were able to physiologically complement the mutant phenotype of diminished PHB synthase activity by making the intracellular environment more reducing. Our data illustrate that the NADPH pool is an important factor for regulation of PHB biosynthesis and metabolism, which is also of interest for potential biotechnological applications. |
Databáze: | OpenAIRE |
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