Crystal structures of a group II chaperonin reveal the open and closed states associated with the protein folding cycle

J Biol Chem. 2010 Sep 3;285(36):27958-66. doi: 10.1074/jbc.M110.125344. Epub 2010 Jun 23.


Chaperonins are large protein complexes consisting of two stacked multisubunit rings, which open and close in an ATP-dependent manner to create a protected environment for protein folding. Here, we describe the first crystal structure of a group II chaperonin in an open conformation. We have obtained structures of the archaeal chaperonin from Methanococcus maripaludis in both a peptide acceptor (open) state and a protein folding (closed) state. In contrast with group I chaperonins, in which the equatorial domains share a similar conformation between the open and closed states and the largest motions occurs at the intermediate and apical domains, the three domains of the archaeal chaperonin subunit reorient as a single rigid body. The large rotation observed from the open state to the closed state results in a 65% decrease of the folding chamber volume and creates a highly hydrophilic surface inside the cage. These results suggest a completely distinct closing mechanism in the group II chaperonins as compared with the group I chaperonins.

Publication types

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

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Crystallography, X-Ray
  • Group II Chaperonins / chemistry*
  • Group II Chaperonins / metabolism
  • Hydrolysis
  • Methanococcus
  • Models, Molecular
  • Protein Folding*
  • Protein Structure, Tertiary


  • Adenosine Triphosphate
  • Group II Chaperonins

Associated data

  • PDB/3KFB
  • PDB/3KFE
  • PDB/3KFK