1U00

HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.178 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

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:  
    1U00

  • 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


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chaperone protein hscA227Escherichia coliMutation(s): 0 
Gene Names: hscA
UniProt
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
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  • Reference Sequence

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • 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
REFMACrefinement
MOSFLMdata reduction
CCP4data scaling
MOLREPphasing

Structure Validation

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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