title: The molecular architecture of the eukaryotic chaperonin TRiC/CCT.
abstract: TRiC/CCT is a highly conserved and essential chaperonin that uses ATP cycling to facilitate folding of approximately 10% of the eukaryotic proteome. This 1 MDa hetero-oligomeric complex consists of two stacked rings of eight paralogous subunits each. Previously proposed TRiC models differ substantially in their subunit arrangements and ring register. Here, we integrate chemical crosslinking, mass spectrometry, and combinatorial modeling to reveal the definitive subunit arrangement of TRiC. In vivo disulfide mapping provided additional validation for the crosslinking-derived arrangement as the definitive TRiC topology. This subunit arrangement allowed the refinement of a structural model using existing X-ray diffraction data. The structure described here explains all available crosslink experiments, provides a rationale for previously unexplained structural features, and reveals a surprising asymmetry of charges within the chaperonin folding chamber.
authors.affiliation: Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Leitner
authors.forename: Lukasz A
authors.initials: LA
authors.lastname: Joachimiak
authors.forename: Andreas
authors.initials: A
authors.lastname: Bracher
authors.forename: Leonie
authors.initials: L
authors.lastname: Mönkemeyer
authors.forename: Thomas
authors.initials: T
authors.lastname: Walzthoeni
authors.forename: Bryan
authors.initials: B
authors.lastname: Chen
authors.forename: Sebastian
authors.initials: S
authors.lastname: Pechmann
authors.forename: Susan
authors.initials: S
authors.lastname: Holmes
authors.forename: Yao
authors.initials: Y
authors.lastname: Cong
authors.forename: Boxue
authors.initials: B
authors.lastname: Ma
authors.forename: Steve
authors.initials: S
authors.lastname: Ludtke
authors.forename: Wah
authors.initials: W
authors.lastname: Chiu
authors.forename: F Ulrich
authors.initials: FU
authors.lastname: Hartl
authors.forename: Ruedi
authors.initials: R
authors.lastname: Aebersold
authors.forename: Judith
authors.initials: J
authors.lastname: Frydman
mesh_terms: D000818:Animals; D002417:Cattle; D056404:Chaperonin Containing TCP-1 / Q000737:chemistry* / Q000378:metabolism; D056890:Eukaryota / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014961:X-Ray Diffraction
chemical_list: D021122:Protein Subunits; D056404:Chaperonin Containing TCP-1