Cysteine Uptake for Accumulation of Glutathione by the Cyanobacterium Synechocystis strain PCC 6803.
By incubation with precursor amino acids, L-glutamate, L-cysteine, and glycine, or with L-cysteine, the unicellular cyanobacterium Synechocystis strain PCC 6803 increased intracellular glutathione levels, under illumination with white light. L-Cystine could not serve as the precursor. Two transport systems for L-cysteine were evident in the strain: a high (Ks; L-cysteine concentration giving one-half of the maximum uptake, 21~35 μM) and a low (Ks, 1.0~1.8 mM) affinity transport system. The latter, responsible for glutathione accumulation, was an energy-requiring process. L-Cysteine uptake by the two transport systems were Na(+)-independent, and inhibited by the presence of neutral amino acids and less inhibited by basic or acidic amino acids. These results suggested that the neutral amino acid symport(s) is involved in L-cysteine uptake for the GSH accumulation in this strain.
a Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
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Suginaka
a Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
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Yamamoto
b Institute for Molecular Genetics, Shimane University.
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Ashiida
a Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
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Kono
a Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
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Saw
a Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
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Shibata
Synechocystis PCC 6803; amino acid transport; cyanobacteria; cysteine uptake; glutathione