FutA1 Synechocystis PCC 6803

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


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

Koropatkin, N.Randich, A.M.Bhattacharyya-Pakrasi, M.Pakrasi, H.B.Smith, T.J.

(2007) J Biol Chem 282: 27468-27477

  • DOI: https://doi.org/10.1074/jbc.M704136200
  • Primary Citation of Related Structures:  
    2PT1, 2PT2, 3F11

  • PubMed 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 beta-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.

  • Organizational Affiliation

    Donald Danforth Plant Science Center, Saint Louis, Missouri 63132 and.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Iron transport protein334Synechocystis sp. PCC 6803Mutation(s): 0 
Gene Names: sufA
Find proteins for P72827 (Synechocystis sp. (strain PCC 6803 / Kazusa))
Explore P72827 
Go to UniProtKB:  P72827
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP72827
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.17α = 90
b = 60.68β = 90
c = 91.7γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
PROTEUM PLUSdata collection
SAINTdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-10
    Type: Initial release
  • Version 1.1: 2007-10-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description