Metabolic flux of the oxidative pentose phosphate pathway under low light conditions in Synechocystis sp. PCC 6803

Publication date: July 2018Source: Journal of Bioscience and Bioengineering, Volume 126, Issue 1Author(s): Kentaro Ueda, Tsubasa Nakajima, Katsunori Yoshikawa, Yoshihiro Toya, Fumio Matsuda, Hiroshi ShimizuThe role of the oxidative pentose phosphate pathway (oxPPP) in Synechocystis sp. PCC 6803 under mixotrophic conditions was investigated by 13C metabolic flux analysis. Cells were cultured under low (10 μmol m−2 s−1) and high light intensities (100 μmol m−2 s−1) in the presence of glucose. The flux of CO2 fixation by ribulose bisphosphate carboxylase/oxygenase under the high light condition was approximately 3-fold higher than that under the low light condition. Although no flux of the oxPPP was observed under the high light condition, flux of 0.08–0.19 mmol gDCW−1 h−1 in the oxPPP was observed under the low light condition. The balance between the consumption and production of NADPH suggested that approximately 10% of the total NADPH production was generated by the oxPPP under the low light condition. The growth phenotype of a mutant with deleted zwf, which encodes glucose-6-phosphate dehydrogenase in the oxPPP, was compared to that of the parental strain under low and high light conditions. Growth of the Δzwf mutant nearly stopped during the late growth phase under the low light condition, whereas the growth rates of the two strains were identical under the high light condition. These results indicate that NADPH production in the oxPPP is essentia...
Source: Journal of Bioscience and Bioengineering - Category: Biomedical Science Source Type: research