title: Functional structure and physiological functions of mammalian wild-type HSP60.
abstract: The Chaperonins comprise a family of molecular chaperones having a double-ring structure and similar sequence homology. These proteins play an essential role in biological reactions that mediate the folding of newly synthesized polypeptides and partially denatured proteins. In the prokaryotic group I chaperonins, structural and reaction cycle analyses of GroEL and its co-chaperone GroES have been performed in detail. While in eukaryotes, there have been limited reports analyzing the group I chaperonin HSP60 and its co-chaperone HSP10. In the present study, we purified the wild type HSP60 from porcine liver and investigated the interaction between HSP60 and HSP10, including conformation and physiological relationships. Based on the results of transmission electron microscopy, native PAGE, and gel filtration column chromatography, the wild type HSP60 displayed a heptameric single-ring structure in the absence of ATP. In contrast, HSP60 formed mainly a "football-type" complex with HSP10 in the presence of ATP and mediated the refolding of denatured substrate protein. The functional conformation cycle of the purified mammalian HSP60 is distinct from the cycle of the prokaryotic GroEL/GroES chaperonin.
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan; Department of Biomolecular Science and Engineering, The Institute of Scientific and Industrial Research, Osaka University, 1-1 Yamadagaoka Suita, Osaka 565-0871, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Ishida
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Tanabe-Ishida
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Haga
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Goto
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan.
authors.forename: Ewa
authors.initials: E
authors.lastname: Grave
authors.affiliation: Department of Life Science, Graduate School and Faculty of Engineering Science, Akita University, Akita 010-8502, Japan. Electronic address: itohh@ipc.akita-u.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Itoh
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D018835:Chaperonin 10 / Q000737:chemistry / Q000378:metabolism; D018834:Chaperonin 60 / Q000737:chemistry* / Q000502:physiology* / Q000648:ultrastructure; D066298:In Vitro Techniques; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D011487:Protein Conformation; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D034421:Sus scrofa
chemical_list: D018835:Chaperonin 10; D018834:Chaperonin 60; D000255:Adenosine Triphosphate
keywords: Chaperonin; Chaperonin homolog; Molecular chaperone; Structure: TEM; Wild-type HSP60