Crystal structure and assembly of a eukaryotic small heat shock protein.
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.
van Montfort
R L
RL
Department of Crystallography, Birkbeck College, Malet Street, London WC1E 7HX UK.
Basha
E
E
Friedrich
K L
KL
Slingsby
C
C
Vierling
E
E
D000595:Amino Acid Sequence; D001120:Arginine / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D017124:Conserved Sequence; D003459:Crystallins / Q000737:chemistry; D018360:Crystallography, X-Ray; D019281:Dimerization; D005057:Eukaryotic Cells / Q000737:chemistry*; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D017017:Methanococcus / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D016415:Sequence Alignment; D014908:Triticum / Q000737:chemistry*
D003459:Crystallins; C101303:HSP16.9 protein, Triticum aestivum; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D021122:Protein Subunits; D001120:Arginine