Crystal structure of a mutant fragment of Human HSPB6

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 

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Molecular structure and dynamics of the dimeric human small heat shock protein HSPB6.

Weeks, S.D.Baranova, E.V.Heirbaut, M.Beelen, S.Shkumatov, A.V.Gusev, N.B.Strelkov, S.V.

(2014) J Struct Biol 185: 342-354

  • DOI: https://doi.org/10.1016/j.jsb.2013.12.009
  • Primary Citation of Related Structures:  
    4JUS, 4JUT

  • PubMed Abstract: 

    ATP-independent small heat-shock proteins (sHSPs) are an essential component of the cellular chaperoning machinery. Under both normal and stress conditions, sHSPs bind partially unfolded proteins and prevent their irreversible aggregation. Canonical vertebrate sHSPs, such as the α-crystallins, form large polydisperse oligomers from which smaller, functionally active subspecies dissociate. Here we focus on human HSPB6 which, despite having considerable homology to the α-crystallins in both the N-terminal region and the signature α-crystallin domain (ACD), only forms dimers in solution that represent the basic chaperoning subspecies. We addressed the three-dimensional structure and functional properties of HSPB6 in a hybrid study employing X-ray crystallography, solution small-angle X-ray scattering (SAXS), mutagenesis, size-exclusion chromatography and chaperoning assays. The crystal structure of a proteolytically stable fragment reveals typical ACD dimers which further form tetrameric assemblies as a result of extensive inter-dimer patching of the β4/β8 grooves. The patching is surprisingly mediated by tripeptide motifs, found in the N-terminal domain directly adjacent to the ACD, that are resembling but distinct from the canonical IxI sequence commonly binding this groove. By combining the crystal structure with SAXS data for the full-length protein, we derive a molecular model of the latter. In solution, HSPB6 shows a strong attractive self-interaction, a property that correlates with its chaperoning activity. Both properties are dictated by the unstructured yet compact N-terminal domain, specifically a region highly conserved across vertebrate sHSPs.

  • Organizational Affiliation

    Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein beta-6
A, B, C, D, E
A, B, C, D, E, F, G, H
107Homo sapiensMutation(s): 2 
Gene Names: HSPB6
UniProt & NIH Common Fund Data Resources
Find proteins for O14558 (Homo sapiens)
Explore O14558 
Go to UniProtKB:  O14558
PHAROS:  O14558
GTEx:  ENSG00000004776 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO14558
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 69.44α = 90
b = 86.01β = 108.21
c = 87.07γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
PDB_EXTRACTdata extraction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-05
    Type: Initial release
  • Version 1.1: 2022-08-24
    Changes: Database references, Derived calculations
  • Version 1.2: 2024-05-29
    Changes: Data collection