HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.178 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


Crystal Structure of the Molecular Chaperone HscA Substrate Binding Domain Complexed with the IscU Recognition Peptide ELPPVKIHC.

Cupp-Vickery, J.R.Peterson, J.C.Ta, D.T.Vickery, L.E.

(2004) J Mol Biol 342: 1265-1278

  • DOI: https://doi.org/10.1016/j.jmb.2004.07.025
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    HscA, a specialized bacterial Hsp70-class molecular chaperone, interacts with the iron-sulfur cluster assembly protein IscU by recognizing a conserved LPPVK sequence motif. We report the crystal structure of the substrate-binding domain of HscA (SBD, residues 389-616) from Escherichia coli bound to an IscU-derived peptide, ELPPVKIHC. The crystals belong to the space group I222 and contain a single molecule in the asymmetric unit. Molecular replacement with the E.coli DnaK(SBD) model was used for phasing, and the HscA(SBD)-peptide model was refined to Rfactor=17.4% (Rfree=21.0%) at 1.95 A resolution. The overall structure of HscA(SBD) is similar to that of DnaK(SBD), although the alpha-helical subdomain (residues 506-613) is shifted up to 10 A relative to the beta-sandwich subdomain (residues 389-498) when compared to DnaK(SBD). The ELPPVKIHC peptide is bound in an extended conformation in a hydrophobic cleft in the beta-subdomain, which appears to be solvent-accessible via a narrow passageway between the alpha and beta-subdomains. The bound peptide is positioned in the reverse orientation of that observed in the DnaK(SBD)-NRLLLTG peptide complex placing the N and C termini of the peptide on opposite sides of the HscA(SBD) relative to the DnaK(SBD) complex. Modeling of the peptide in the DnaK-like forward orientation suggests that differences in hydrogen bonding interactions in the binding cleft and electrostatic interactions involving surface residues near the cleft contribute to the observed directional preference.

  • Organizational Affiliation

    Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA. jvickery@uci.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chaperone protein hscA227Escherichia coliMutation(s): 0 
Gene Names: hscA
Find proteins for P0A6Z1 (Escherichia coli (strain K12))
Explore P0A6Z1 
Go to UniProtKB:  P0A6Z1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A6Z1
Sequence Annotations
  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
IscU recognition peptideB [auth P]9N/AMutation(s): 0 
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.178 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.761α = 90
b = 83.34β = 90
c = 128.734γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
CCP4data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-10-05
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references
  • Version 1.4: 2024-04-03
    Changes: Refinement description