title: Universal behavior in the mesoscale properties of amyloid fibrils.
abstract: Amyloid fibrils are ubiquitous proteinaceous aggregates occurring in vivo and in vitro, with an invariant structural fingerprint at the molecular length scale. However, interpretation of their mesoscopic architectures is complicated by diverse observable polymorphic states. We here present a constitutive model for amyloid fibrils based on the minimization of the total energy per fibril. The model is benchmarked on real amyloid fibrils studied by atomic force microscopy. We use multistranded β-lactoglobulin amyloid fibrils as a model system exhibiting a rich polymorphism. The constitutive model quantitatively recapitulates the main mesoscopic topological features of amyloid fibrils, that is, the evolution of fibril periodicity as a function of the ionic strength of the solution and of the fibril width. A universal mesoscopic structural signature of the fibrils emerges from this picture, predicting a general, parameter-free law for the periodicity of the fibrils, that depends solely on the number of protofilaments per fibril. These predictions are validated experimentally and conclusively highlight the role of competing electrostatic and elastic contributions as the main players in the establishment of amyloid fibrils structure.
authors.affiliation: Laboratoire de Biophysique Statistique, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Assenza
authors.affiliation: ETH Zurich, Food and Soft Materials Science, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland.
authors.forename: Jozef
authors.initials: J
authors.lastname: Adamcik
authors.affiliation: ETH Zurich, Food and Soft Materials Science, Department of Health Science and Technology, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, CH-8092 Zurich, Switzerland.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
authors.affiliation: Laboratoire de Biophysique Statistique, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Paolo
authors.initials: P
authors.lastname: De Los Rios
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D003460:Crystallization; D004548:Elasticity; D007782:Lactoglobulins / Q000737:chemistry; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D017433:Protein Structure, Secondary; D055672:Static Electricity
chemical_list: D000682:Amyloid; D007782:Lactoglobulins