Stress-induced protein 1 truncation mutant (43 - 140) from Caenorhabditis elegans

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 

wwPDB Validation   3D Report Full Report

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The Chaperone Activity of the Developmental Small Heat Shock Protein Sip1 Is Regulated by pH-Dependent Conformational Changes.

Fleckenstein, T.Kastenmuller, A.Stein, M.L.Peters, C.Daake, M.Krause, M.Weinfurtner, D.Haslbeck, M.Weinkauf, S.Groll, M.Buchner, J.

(2015) Mol Cell 58: 1067-1078

  • DOI: https://doi.org/10.1016/j.molcel.2015.04.019
  • Primary Citation of Related Structures:  
    4YDZ, 4YE0

  • PubMed Abstract: 

    Small heat shock proteins (sHsps) are ubiquitous molecular chaperones that prevent the aggregation of unfolding proteins during proteotoxic stress. In Caenorhabditis elegans, Sip1 is the only sHsp exclusively expressed in oocytes and embryos. Here, we demonstrate that Sip1 is essential for heat shock survival of reproducing adults and embryos. X-ray crystallography and electron microscopy revealed that Sip1 exists in a range of well-defined globular assemblies consisting of two half-spheres, each made of dimeric "spokes." Strikingly, the oligomeric distribution of Sip1 as well as its chaperone activity depend on pH, with a trend toward smaller species and higher activity at acidic conditions such as present in nematode eggs. The analysis of the interactome shows that Sip1 has a specific substrate spectrum including proteins that are essential for embryo development.

  • Organizational Affiliation

    Center for Integrated Protein Science, Fakultät für Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Stress-induced protein 1
A, B
119Caenorhabditis elegansMutation(s): 0 
Gene Names: sip-1F43D9.4
Find proteins for Q20363 (Caenorhabditis elegans)
Explore Q20363 
Go to UniProtKB:  Q20363
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ20363
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.39α = 90
b = 50.82β = 90
c = 130.17γ = 90
Software Package:
Software NamePurpose
XDSdata reduction

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
German Research FoundationGermanySFB1035

Revision History  (Full details and data files)

  • Version 1.0: 2015-06-10
    Type: Initial release
  • Version 1.1: 2015-07-01
    Changes: Database references
  • Version 2.0: 2024-05-08
    Changes: Atomic model, Author supporting evidence, Data collection, Database references, Refinement description