title: Adsorption at liquid interfaces induces amyloid fibril bending and ring formation.
abstract: Protein fibril accumulation at interfaces is an important step in many physiological processes and neurodegenerative diseases as well as in designing materials. Here we show, using β-lactoglobulin fibrils as a model, that semiflexible fibrils exposed to a surface do not possess the Gaussian distribution of curvatures characteristic for wormlike chains, but instead exhibit a spontaneous curvature, which can even lead to ring-like conformations. The long-lived presence of such rings is confirmed by atomic force microscopy, cryogenic scanning electron microscopy, and passive probe particle tracking at air- and oil-water interfaces. We reason that this spontaneous curvature is governed by structural characteristics on the molecular level and is to be expected when a chiral and polar fibril is placed in an inhomogeneous environment such as an interface. By testing β-lactoglobulin fibrils with varying average thicknesses, we conclude that fibril thickness plays a determining role in the propensity to form rings.
authors.affiliation: Department of Health Sciences & Technology, Laboratory of Food & Soft Materials, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: Sophia
authors.initials: S
authors.lastname: Jordens
authors.forename: Emily E
authors.initials: EE
authors.lastname: Riley
authors.forename: Ivan
authors.initials: I
authors.lastname: Usov
authors.forename: Lucio
authors.initials: L
authors.lastname: Isa
authors.forename: Peter D
authors.initials: PD
authors.lastname: Olmsted
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
mesh_terms: D000327:Adsorption; D000682:Amyloid / Q000737:chemistry*; D007782:Lactoglobulins / Q000737:chemistry; D018625:Microscopy, Atomic Force; D011487:Protein Conformation
chemical_list: D000682:Amyloid; D007782:Lactoglobulins
keywords: amyloid fibrils; atomic force microscopy; bending; biopolymers; interfaces; statistical analysis; β-lactoglobulin