Involvement of polyamine binding protein D (PotD) of Synechocystis sp. PCC 6803 in spermidine uptake and excretion.
The in vivo function of polyamine binding protein D (PotD) in Synechocystis sp. PCC 6803 for the transport of spermidine was investigated using Synechocystis mutant disrupted in potD gene. The growth rate of potD mutant was similar to that of wild-type when grown in BG11 medium. However, the mutant exhibited severely reduced growth compared to the wild-type when BG11 medium was supplemented with 0.5 mM spermidine. The mutant accumulated a higher spermidine level than the wild-type when grown in the medium with or without spermidine. Transport experiments revealed that the mutant had a reduction in both the uptake and the excretion of spermidine. Moreover, [(14)C]spermidine-loaded wild-type and mutant cells showed a decrease of [(14)C]spermidine excretion when the assay medium contained exogenous spermidine. These data suggest that PotD is involved in both the uptake and the excretion of spermidine in Synechocystis cells.
Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Panutda
P
Yodsang
Apiradee
A
Pothipongsa
Pirkko
P
Mäenpää
Aran
A
Incharoensakdi
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D011073:Polyamines / Q000378:metabolism*; D013095:Spermidine / Q000378:metabolism*; D046939:Synechocystis / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011073:Polyamines; D013095:Spermidine