The structure of the iron-binding protein, FutA1, from Synechocystis 6803

Nicole Koropatkin, Amelia M. Randich, Maitrayee Bhattacharyya-Pakrasi, Himadri B. Pakrasi, Thomas Smith

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Cyanobacteria account for a significant percentage of aquatic primary productivity even in areas where the concentrations of essential micronutrients are extremely low. To better understand the mechanism of iron selectivity and transport, the structure of the solute binding domain of an ATP binding cassette iron transporter, FutA1, was determined in the presence and absence of iron. The iron ion is bound within the "C-clamp" structure via four tyrosine and one histidine residues. There are extensive interactions between these ligating residues and the rest of the protein such that the conformations of the side chains remain relatively unchanged as the iron is released by the opening of the metal binding cleft. This is in stark contrast to the zinc-binding protein, ZnuA, where the domains of the metal-binding protein remain relatively fixed, whereas the ligating residues rotate out of the binding pocket upon metal release. The rotation of the domains in FutA1 is facilitated by two flexible β-strands running along the back of the protein that act like a hinge during domain motion. This motion may require relatively little energy since total contact area between the domains is the same whether the protein is in the open or closed conformation. Consistent with the pH dependence of iron binding, the main trigger for iron release is likely the histidine in the iron-binding site. Finally, neither FutA1 nor FutA2 binds iron as a siderophore complex or in the presence of anions, and both preferentially bind ferrous over ferric ions.

Original languageEnglish (US)
Pages (from-to)27468-27477
Number of pages10
JournalJournal of Biological Chemistry
Volume282
Issue number37
DOIs
StatePublished - Sep 14 2007
Externally publishedYes

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Iron-Binding Proteins
Synechocystis
Iron
Metals
Histidine
Conformations
Ions
Siderophores
Protein Conformation
Proteins
ATP-Binding Cassette Transporters
Micronutrients
Clamping devices
Cyanobacteria
Hinges
Anions
Tyrosine
Carrier Proteins
Adenosine Triphosphate
Productivity

ASJC Scopus subject areas

  • Biochemistry

Cite this

Koropatkin, N., Randich, A. M., Bhattacharyya-Pakrasi, M., Pakrasi, H. B., & Smith, T. (2007). The structure of the iron-binding protein, FutA1, from Synechocystis 6803. Journal of Biological Chemistry, 282(37), 27468-27477. https://doi.org/10.1074/jbc.M704136200

The structure of the iron-binding protein, FutA1, from Synechocystis 6803. / Koropatkin, Nicole; Randich, Amelia M.; Bhattacharyya-Pakrasi, Maitrayee; Pakrasi, Himadri B.; Smith, Thomas.

In: Journal of Biological Chemistry, Vol. 282, No. 37, 14.09.2007, p. 27468-27477.

Research output: Contribution to journalArticle

Koropatkin, N, Randich, AM, Bhattacharyya-Pakrasi, M, Pakrasi, HB & Smith, T 2007, 'The structure of the iron-binding protein, FutA1, from Synechocystis 6803', Journal of Biological Chemistry, vol. 282, no. 37, pp. 27468-27477. https://doi.org/10.1074/jbc.M704136200
Koropatkin, Nicole ; Randich, Amelia M. ; Bhattacharyya-Pakrasi, Maitrayee ; Pakrasi, Himadri B. ; Smith, Thomas. / The structure of the iron-binding protein, FutA1, from Synechocystis 6803. In: Journal of Biological Chemistry. 2007 ; Vol. 282, No. 37. pp. 27468-27477.
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