Pseudo-atomic model for Hsp26 residues 63 to 214. Please be advised that the target map is not of sufficient resolution to unambiguously position backbone or side chain atoms. This model represents a likely fit.

Experimental Data Snapshot

  • Resolution: 7.80 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

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Phosphorylation activates the yeast small heat shock protein Hsp26 by weakening domain contacts in the oligomer ensemble.

Muhlhofer, M.Peters, C.Kriehuber, T.Kreuzeder, M.Kazman, P.Rodina, N.Reif, B.Haslbeck, M.Weinkauf, S.Buchner, J.

(2021) Nat Commun 12: 6697-6697

  • DOI: https://doi.org/10.1038/s41467-021-27036-7
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Hsp26 is a small heat shock protein (sHsp) from S. cerevisiae. Its chaperone activity is activated by oligomer dissociation at heat shock temperatures. Hsp26 contains 9 phosphorylation sites in different structural elements. Our analysis of phospho-mimetic mutations shows that phosphorylation activates Hsp26 at permissive temperatures. The cryo-EM structure of the Hsp26 40mer revealed contacts between the conserved core domain of Hsp26 and the so-called thermosensor domain in the N-terminal part of the protein, which are targeted by phosphorylation. Furthermore, several phosphorylation sites in the C-terminal extension, which link subunits within the oligomer, are sensitive to the introduction of negative charges. In all cases, the intrinsic inhibition of chaperone activity is relieved and the N-terminal domain becomes accessible for substrate protein binding. The weakening of domain interactions within and between subunits by phosphorylation to activate the chaperone activity in response to proteotoxic stresses independent of heat stress could be a general regulation principle of sHsps.

  • Organizational Affiliation

    Center for Protein Assemblies, Department of Chemistry, Technische Universität München, Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Heat shock protein 26A,
C [auth I],
D [auth J],
E [auth X]
214Saccharomyces cerevisiae S288CMutation(s): 0 
Gene Names: HSP26YBR072WYBR0714
Find proteins for P15992 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore P15992 
Go to UniProtKB:  P15992
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP15992
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 7.80 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
German Research Foundation (DFG)GermanySFB 1035

Revision History  (Full details and data files)

  • Version 1.0: 2021-11-24
    Type: Initial release
  • Version 1.1: 2021-12-01
    Changes: Database references