title: Inhibition of tau aggregation using a naturally-occurring cyclic peptide scaffold.
abstract: Disulfide-rich macrocyclic peptides are emerging as versatile scaffolds for the development of stable biochemical tools. This potential is due to the combination of their structural stability and range of bioactivities. Here, we explored the activity of these peptides on fibril growth of the hexapeptide Ac-VQIVYK-NH2 (AcPHF6), which is a tau-derived peptide that has been widely used to understand the pathological mechanism of numerous tauopathies, including Alzheimer's disease. Of the cyclic peptides tested, SFTI-1 and kB1 showed an inherent ability to inhibit AcPHF6 fibril formation. Using an end-capping strategy and combining it with a molecular grafting approach, we demonstrated that SFTI-1 could be used as a starting point to design more potent fibril inhibitors. We further identified chemical and structural features of SFTI-1 and its analogues that underpin their inhibitory activity. The ability to inhibit fibril growth using the strategy employed herein supports the 'steric zipper' model of AcPHF6 fibril formation and shows that naturally-occurring cyclic peptides have potential as drug leads or molecular probes for understanding fibril formation.
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia. Electronic address: c.wang@imb.uq.edu.au.
authors.forename: Conan K
authors.initials: CK
authors.lastname: Wang
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Northfield
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia.
authors.forename: Yen-Hua
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia.
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Ramos
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, 4072, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Craik
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D015195:Drug Design; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000494:pharmacology*; D066329:Protein Aggregates / Q000187:drug effects*; D066263:Protein Aggregation, Pathological / Q000188:drug therapy / Q000378:metabolism; D016415:Sequence Alignment; D024801:Tauopathies / Q000188:drug therapy* / Q000378:metabolism; D016875:tau Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000682:Amyloid; D009842:Oligopeptides; D010456:Peptides, Cyclic; D066329:Protein Aggregates; C510485:acetyl-valyl-glutaminyl-isoleucyl-valyl-tyrosyl-lysinamide; D016875:tau Proteins
keywords: Aggregation; Amyloid; Cyclic peptide; Disulfide bond; Molecular grafting