title: Amyloid-like fibril formation of co-chaperonin GroES: nucleation and extension prefer different degrees of molecular compactness.
abstract: The molecular chaperone GroES, together with GroEL from Escherichia coli, is the best characterized protein of the molecular chaperone family. Here, we report on the in vitro formation of GroES amyloid-like fibrils and the mechanism of formation. When incubated for several weeks at neutral pH in the presence of the denaturant guanidine hydrochloride, GroES formed a typical amyloid fibril; unbranched, twisted, and extended filaments stainable by thioflavin T and Congo red. GroES fibril formation was accelerated by the addition of preformed fibril seeds, in accordance with a nucleation-extension mechanism. Interestingly, whereas the spontaneous formation of GroES fibrils was favored in the structural transition region of GroES dissociation/unfolding, the extension of fibrils from preformed fibril seeds was favored in the region corresponding to an expanded molecular state. We concluded that the two stages of GroES fibril formation prefer different molecular states of the same protein. The significance of this preference is discussed.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Koyama-Minami, Tottori 680-8552, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Higurashi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yagi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Mizobata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawata
mesh_terms: D000682:Amyloid / Q000737:chemistry; D052160:Benzothiazoles; D002352:Carrier Proteins / Q000737:chemistry; D018835:Chaperonin 10 / Q000737:chemistry*; D002942:Circular Dichroism; D004396:Coloring Agents / Q000494:pharmacology; D003224:Congo Red / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D019791:Guanidine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008027:Light; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008968:Molecular Conformation; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000682:Amyloid; D052160:Benzothiazoles; D002352:Carrier Proteins; D018835:Chaperonin 10; D004396:Coloring Agents; D013844:Thiazoles; C009462:thioflavin T; D003224:Congo Red; D019791:Guanidine