title: Molecular clamp mechanism of substrate binding by hydrophobic coiled-coil residues of the archaeal chaperone prefoldin.
abstract: Prefoldin (PFD) is a jellyfish-shaped molecular chaperone that has been proposed to play a general role in de novo protein folding in archaea and is known to assist the biogenesis of actins, tubulins, and potentially other proteins in eukaryotes. Using point mutants, chimeras, and intradomain swap variants, we show that the six coiled-coil tentacles of archaeal PFD act in concert to bind and stabilize nonnative proteins near the opening of the cavity they form. Importantly, the interaction between chaperone and substrate depends on the mostly buried interhelical hydrophobic residues of the coiled coils. We also show by electron microscopy that the tentacles can undergo an en bloc movement to accommodate an unfolded substrate. Our data reveal how archael PFD uses its unique architecture and intrinsic coiled-coil properties to interact with nonnative polypeptides.
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6.
authors.forename: Victor F
authors.initials: VF
authors.lastname: Lundin
authors.forename: Peter C
authors.initials: PC
authors.lastname: Stirling
authors.forename: Juan
authors.initials: J
authors.lastname: Gomez-Reino
authors.forename: Jill C
authors.initials: JC
authors.lastname: Mwenifumbo
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Obst
authors.forename: José M
authors.initials: JM
authors.lastname: Valpuesta
authors.forename: Michel R
authors.initials: MR
authors.lastname: Leroux
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D002850:Chromatography, Gel; D007700:Kinetics; D018832:Molecular Chaperones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C112806:prefoldin