Journal
PLANT AND CELL PHYSIOLOGY
Volume 42, Issue 8, Pages 823-827Publisher
OXFORD UNIV PRESS
DOI: 10.1093/pcp/pce106
Keywords
cyanobacterium; FutA1; iron transporter; periplasmic binding protein; Synechocystis sp PCC 6803
Categories
Ask authors/readers for more resources
The futA1 (slr1295) and futA2 (slr0513) genes encode periplasmic binding proteins of an ATP-binding cassette (A-BC)-type iron transporter in Synechocystis sp. PCC 6803. FutA1 was expressed in Escherichia coli as a GST-tagged recombinant protein (rFutA1). Solution containing purified rFutA1 and ferric chloride showed an absorption spectrum with a peak at 453 nm. The absorbance at this wavelength rose linearly as the amount of iron bound to rFutA1 increased to reach a plateau when the molar ratio of iron to rFutA1 became unity. The association constant of rFutA1 for iron in vitro was about 1x10(19). These results demonstrate that the FutA1 binds the ferric ion with high affinity. The activity of iron uptake in the Delta futA1 and Delta futA2 mutants was 37 and 84%, respectively, of that in the wildtype and the activity was less than 5% in the Delta futA1/Delta futA2 double mutant, suggesting their redundant role for binding iron. High concentrations of citrate inhibited ferric iron uptake. These results suggest that the natural iron source transported by the Fut system is not ferric citrate.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available