title: Modulating the Effects of the Bacterial Chaperonin GroEL on Fibrillogenic Polypeptides through Modification of Domain Hinge Architecture.
abstract: The isolated apical domain of the Escherichia coli GroEL subunit displays the ability to suppress the irreversible fibrillation of numerous amyloid-forming polypeptides. In previous experiments, we have shown that mutating Gly-192 (located at hinge II that connects the apical domain and the intermediate domain) to a tryptophan results in an inactive chaperonin whose apical domain is disoriented. In this study, we have utilized this disruptive effect of Gly-192 mutation to our advantage, by substituting this residue with amino acid residues of varying van der Waals volumes with the intent to modulate the affinity of GroEL toward fibrillogenic peptides. The affinities of GroEL toward fibrillogenic polypeptides such as Aβ(1-40) (amyloid-β(1-40)) peptide and α-synuclein increased in accordance to the larger van der Waals volume of the substituent amino acid side chain in the G192X mutants. When we compared the effects of wild-type GroEL and selected GroEL G192X mutants on α-synuclein fibril formation, we found that the effects of the chaperonin on α-synuclein fibrillation were different; the wild-type chaperonin caused changes in both the initial lag phase and the rate of fibril extension, whereas the effects of the G192X mutants were more specific toward the nucleus-forming lag phase. The chaperonins also displayed differential effects on α-synuclein fibril morphology, suggesting that through mutation of Gly-192, we may induce changes to the intermolecular affinities between GroEL and α-synuclein, leading to more efficient fibril suppression, and in specific cases, modulation of fibril morphology.
authors.affiliation: From the Department of Chemistry and Biotechnology, Graduate School of Engineering, and.
authors.forename: Naoya
authors.initials: N
authors.lastname: Fukui
authors.affiliation: From the Department of Chemistry and Biotechnology, Graduate School of Engineering, and.
authors.forename: Kiho
authors.initials: K
authors.lastname: Araki
authors.affiliation: From the Department of Chemistry and Biotechnology, Graduate School of Engineering, and.|the Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori 680-8552, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Hongo
authors.affiliation: From the Department of Chemistry and Biotechnology, Graduate School of Engineering, and.|the Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori 680-8552, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Mizobata
authors.affiliation: From the Department of Chemistry and Biotechnology, Graduate School of Engineering, and kawata@bio.tottori-u.ac.jp.|the Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori 680-8552, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawata
mesh_terms: D019943:Amino Acid Substitution; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018834:Chaperonin 60 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D066329:Protein Aggregates; D051844:alpha-Synuclein / Q000737:chemistry* / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D066329:Protein Aggregates; C497604:SNCA protein, human; D051844:alpha-Synuclein; C078592:amyloid beta-protein (1-40)
keywords: GroEL; alpha-synuclein (a-synuclein); amyloid fibrils; chaperonin; protein aggregation; protein engineering; protein misfolding; protein-protein interaction