Journal Article

Iron-Binding Activity of FutA1 Subunit of an ABC-type Iron Transporter in the Cyanobacterium <i>Synechocystis</i> sp. Strain PCC 6803

Hirokazu Katoh, Natsu Hagino and Teruo Ogawa

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 42, issue 8, pages 823-827
Published in print August 2001 | ISSN: 0032-0781
Published online August 2001 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pce106
Iron-Binding Activity of FutA1 Subunit of an ABC-type Iron Transporter in the Cyanobacterium Synechocystis sp. Strain PCC 6803

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

The futA1 (slr1295) and futA2 (slr0513) genes encode periplasmic binding proteins of an ATP-binding cassette (ABC)-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 1×1019. These results demonstrate that the FutA1 binds the ferric ion with high affinity. The activity of iron uptake in the ΔfutA1 and ΔfutA2 mutants was 37 and 84%, respectively, of that in the wild-type and the activity was less than 5% in the ΔfutA1futA2 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.

Keywords: Key words: Cyanobacterium — FutA1 — Iron transporter — Periplasmic binding protein — Synechocystis sp. PCC 6803.; Abbreviations: ABC, ATP-binding cassette; GST, Glutathione S-transferase; rFutA1, recombinant FutA1; IPTG, isopropyl-1-thio-β-d-galactopyranoside; PBS, phosphate-buffered saline.

Journal Article.  3513 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.