Crystal structure and assembly of a eukaryotic small heat shock protein

Nat Struct Biol. 2001 Dec;8(12):1025-30. doi: 10.1038/nsb722.


The 2.7 A structure of wheat HSP16.9, a member of the small heat shock proteins (sHSPs), indicates how its alpha-crystallin domain and flanking extensions assemble into a dodecameric double disk. The folding of the monomer and assembly of the oligomer are mutually interdependent, involving strand exchange, helix swapping, loose knots and hinged extensions. In support of the chaperone mechanism, the substrate-bound dimers, in temperature-dependent equilibrium with higher assembly forms, have unfolded N-terminal arms and exposed conserved hydrophobic binding sites on the alpha-crystallin domain. The structure also provides a model by which members of the sHSP protein family bind unfolded substrates, which are involved in a variety of neurodegenerative diseases and cataract formation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Arginine / genetics
  • Arginine / metabolism
  • Binding Sites
  • Conserved Sequence
  • Crystallins / chemistry
  • Crystallography, X-Ray
  • Dimerization
  • Eukaryotic Cells / chemistry*
  • Heat-Shock Proteins / chemistry*
  • Heat-Shock Proteins / metabolism*
  • Methanococcus / chemistry
  • Models, Molecular
  • Molecular Sequence Data
  • Plant Proteins / chemistry
  • Plant Proteins / metabolism
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Protein Subunits
  • Sequence Alignment
  • Triticum / chemistry*


  • Crystallins
  • HSP16.9 protein, Triticum aestivum
  • Heat-Shock Proteins
  • Plant Proteins
  • Protein Subunits
  • Arginine

Associated data

  • PDB/1GME