title: Crystal structure of the thermosome, the archaeal chaperonin and homolog of CCT.
abstract: We have determined to 2.6 A resolution the crystal structure of the thermosome, the archaeal group II chaperonin from T. acidophilum. The hexadecameric homolog of the eukaryotic chaperonin CCT/TRiC shows an (alphabeta)4(alphabeta)4 subunit assembly. Domain folds are homologous to GroEL but form a novel type of inter-ring contact. The domain arrangement resembles the GroEL-GroES cis-ring. Parts of the apical domains form a lid creating a closed conformation. The lid substitutes for a GroES-like cochaperonin that is absent in the CCT/TRiC system. The central cavity has a polar surface implicated in protein folding. Binding of the transition state analog Mg-ADP-AIF3 suggests that the closed conformation corresponds to the ATP form.
authors.affiliation: Max-Planck-Institut für Biochemie, Martinsried, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Ditzel
authors.forename: J
authors.initials: J
authors.lastname: Löwe
authors.forename: D
authors.initials: D
authors.lastname: Stock
authors.forename: K O
authors.initials: KO
authors.lastname: Stetter
authors.forename: H
authors.initials: H
authors.lastname: Huber
authors.forename: R
authors.initials: R
authors.lastname: Huber
authors.forename: S
authors.initials: S
authors.lastname: Steinbacher
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001105:Archaea / Q000378:metabolism*; D019843:Archaeal Proteins; D018833:Chaperonins / Q000737:chemistry* / Q000378:metabolism*; D003198:Computer Simulation; D018360:Crystallography, X-Ray / Q000379:methods; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D056405:Thermosomes; D044767:Ubiquitin-Protein Ligases; D056427:t-Complex Genome Region
chemical_list: D019843:Archaeal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; C116196:PPP1R11 protein, human; D044767:Ubiquitin-Protein Ligases; D018833:Chaperonins; D056405:Thermosomes