Native Form 2 E.coli Chaperone Hsp31

Experimental Data Snapshot

  • Resolution: 2.71 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.225 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


A new native EcHsp31 structure suggests a key role of structural flexibility for chaperone function.

Quigley, P.M.Korotkov, K.Baneyx, F.Hol, W.G.J.

(2004) Protein Sci 13: 269-277

  • DOI: https://doi.org/10.1110/ps.03399604
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Heat shock proteins and proteases play a crucial role in cell survival under conditions of environmental stress. The heat shock protein Hsp31, produced by gene hchA at elevated temperatures in Escherichia coli, is a homodimeric protein consisting of a large A domain and a smaller P domain connected by a linker. Two catalytic triads are present per dimer, with the Cys and His contributed by the A domain and an Asp by the P domain. A new crystal Form II confirms the dimer and catalytic triad arrangement seen in the earlier crystal Form I. In addition, several loops exhibit increased flexibility compared to the previous Hsp31 dimer structure. In particular, loops D2 and D3 are intriguing because their mobility leads to the exposure of a sizable hydrophobic patch made up by surface areas of both subunits near the dimer interface. The residues creating this hydrophobic surface are completely conserved in the Hsp31 family. At the same time, access to the catalytic triad is increased. These observations lead to the hypothesis for the functioning of Hsp31 wherein loops D2 and D3 play a key role: first, at elevated temperatures, by becoming mobile and uncovering a large hydrophobic area that helps in binding to client proteins, and second, by removing the client protein from the hydrophobic patch when the temperature decreases and the loops adopt their low-temperature positions at the Hsp31 surface. The proposed mode of action of flexible loops in the functioning of Hsp31 may be a general principle employed by other chaperones.

  • Organizational Affiliation

    Department of Biochemistry, Department of Chemical Engineering, and Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195-7742, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chaperone protein hchA
A, B, C, D, E
A, B, C, D, E, F, G, H
283Escherichia coliMutation(s): 0 
Gene Names: HCHA OR B1967
EC: 3.1.2 (UniProt), 3.5.1 (UniProt), (UniProt), (UniProt)
Find proteins for P31658 (Escherichia coli (strain K12))
Explore P31658 
Go to UniProtKB:  P31658
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP31658
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.71 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.225 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.487α = 102.95
b = 99.018β = 101.52
c = 116.795γ = 94.19
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-01-13
    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: 2022-12-21
    Changes: Database references
  • Version 1.4: 2023-09-20
    Changes: Data collection, Refinement description