title: Conformational memory effect reverses chirality of vortex-induced insulin amyloid superstructures.
abstract: Formation of amyloid fibrils is often associated with intriguing far-from-equilibrium phenomena such as conformational memory effects or flow-driven self-assembly. Insulin is a model amyloidogenic polypeptide forming distinct structural variants of fibrils, which self-propagate through seeding. According to infrared absorption, fibrils from bovine insulin ([BI]) and Lys(B31)-Arg(B32) human insulin analogue ([KR]) cross-seed each other and imprint distinct structural features in daughter fibrils. In the absence of preformed [KR] amyloid seeds, bovine insulin agitated at 60 °C converts into chiral amyloid superstructures exhibiting negative extrinsic Cotton effect in bound thioflavin T. However, when agitated bovine insulin is simultaneously cross-seeded with [KR] amyloid, daughter fibrils reveal a positive extrinsic Cotton effect. Our study indicates that dramatic changes in global properties of amyloid superstructures may emerge from subtle conformational-level variations in single fibrils (e.g., alignment and twist of β-strands) that are encoded by memory effects.
authors.affiliation: Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland. wdzwolak@chem.uw.edu.pl
authors.forename: Wojciech
authors.initials: W
authors.lastname: Dzwolak
authors.forename: Weronika
authors.initials: W
authors.lastname: Surmacz-Chwedoruk
authors.forename: Viktoria
authors.initials: V
authors.lastname: Babenko
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D006801:Humans; D057446:Hydrodynamics; D007328:Insulin / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013237:Stereoisomerism
chemical_list: D000682:Amyloid; D007328:Insulin