Crystal structure of group II chaperonin in the open state

Structure. 2010 Oct 13;18(10):1270-9. doi: 10.1016/j.str.2010.07.009.


Thermosomes are group II chaperonins responsible for protein refolding in an ATP-dependent manner. Little is known regarding the conformational changes of thermosomes during their functional cycle due to a lack of high-resolution structure in the open state. Here, we report the first complete crystal structure of thermosome (rATcpnβ) in the open state from Acidianus tengchongensis. There is a ∼30° rotation of the apical and lid domains compared with the previous closed structure. Besides, the structure reveals a conspicuous hydrophobic patch in the lid domain, and residues locating in this patch are conserved across species. Both the closed and open forms of rATcpnβ were also reconstructed by electron microscopy (EM). Structural fitting revealed the detailed conformational change from the open to the closed state. Structural comparison as well as protease K digestion indicated only ATP binding without hydrolysis does not induce chamber closure of thermosome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acidianus / metabolism
  • Adenosine Diphosphate / chemistry
  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / chemistry
  • Adenosine Triphosphate / metabolism
  • Archaeal Proteins / chemistry*
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism
  • Cloning, Molecular
  • Cryoelectron Microscopy
  • Crystallization
  • Electrophoresis, Polyacrylamide Gel
  • Models, Molecular
  • Protein Binding
  • Protein Conformation*
  • Protein Folding
  • Protein Structure, Tertiary
  • Thermosomes / chemistry*
  • Thermosomes / genetics
  • Thermosomes / metabolism
  • X-Ray Diffraction


  • Archaeal Proteins
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Thermosomes

Associated data

  • PDB/3KO1