Crystal Structure of IscA (native)

Experimental Data Snapshot

  • Resolution: 2.65 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 

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This is version 1.4 of the entry. See complete history


Crystal structure of the ancient, Fe-S scaffold IscA reveals a novel protein fold.

Bilder, P.W.Ding, H.Newcomer, M.E.

(2004) Biochemistry 43: 133-139

  • DOI: https://doi.org/10.1021/bi035440s
  • Primary Citation of Related Structures:  
    1R94, 1R95

  • PubMed Abstract: 

    IscA belongs to an ancient family of proteins responsible for iron-sulfur cluster assembly in essential metabolic pathways preserved throughout evolution. We report here the 2.3 A resolution crystal structure of Escherichia coli IscA, a novel fold in which mixed beta-sheets form a compact alpha-beta sandwich domain. In contrast to the highly mobile secondary structural elements within the bacterial Fe-S scaffold protein IscU, a protein which is thought to have a similar function, the great majority of the amino acids that are conserved in IscA homologues are located in elements that constitute a well-ordered fold. However, the 10-residue C-terminal tail segment that contains two invariant cysteines critical for the Fe-S-binding function of a cyanobacterial (Synechocystis PCC) IscA homologue is not ordered in our structure. In addition, the crystal packing reveals a helical assembly that is constructed from two possible tetrameric oligomers of IscA.

  • Organizational Affiliation

    Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protein yfhF
A, B
118Escherichia coliMutation(s): 0 
Gene Names: YFHFB2528C3053Z3795ECS3394SF2575S2747
Find proteins for P0AAC8 (Escherichia coli (strain K12))
Explore P0AAC8 
Go to UniProtKB:  P0AAC8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0AAC8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.65 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 
  • Space Group: P 62
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.527α = 90
b = 55.527β = 90
c = 159.037γ = 120
Software Package:
Software NamePurpose
MAR345data collection
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-12-23
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2024-02-14
    Changes: Data collection, Database references, Refinement description