Volume 127, Issue 8 p. 2492-2496
Zuschrift

Influence of the β-Sheet Content on the Mechanical Properties of Aggregates during Amyloid Fibrillization

Francesco Simone Ruggeri,

Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), Route de la Sorge, 1015 Lausanne (Switzerland)

These authors contributed equally.

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Dr. Jozef Adamcik,

Food and Soft Materials Science, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, LFO E23, 8092, Zürich (Switzerland)

These authors contributed equally.

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Jae Sun Jeong,

Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), Route de la Sorge, 1015 Lausanne (Switzerland)

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Prof. Hilal A. Lashuel,

Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

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Prof. Raffaele Mezzenga,

Corresponding Author

Food and Soft Materials Science, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, LFO E23, 8092, Zürich (Switzerland)

Raffaele Mezzenga, Food and Soft Materials Science, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, LFO E23, 8092, Zürich (Switzerland)

Giovanni Dietler, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), Route de la Sorge, 1015 Lausanne (Switzerland)

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Prof. Giovanni Dietler,

Corresponding Author

Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), Route de la Sorge, 1015 Lausanne (Switzerland)

Raffaele Mezzenga, Food and Soft Materials Science, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, LFO E23, 8092, Zürich (Switzerland)

Giovanni Dietler, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), Route de la Sorge, 1015 Lausanne (Switzerland)

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First published: 14 January 2015
Citations: 13

We thank the Swiss National Foundation for Science for financial support (Project Number 152958).

Abstract

Kraftmessung: Bei der Amyloidfaserbildung, die mit neurodegenerativen Krankheiten assoziiert ist, aggregieren anfänglich gebildete oligomere und protofibrilläre Spezies zu Fasern mit gekreuzter β-Faltblatt-Struktur (siehe Bild). Quantitative nanomechanische AFM-Kraftmessungen offenbaren einen Anstieg des Young-Moduls während der Faserbildung, einhergehend mit einem Anstieg des Anteils an β-Faltblättern.

Abstract

Amyloid fibrils associated with neurodegenerative diseases, such as Parkinson’s and Alzheimer’s, consist of insoluble aggregates of α-synuclein and Aβ-42 proteins with a high β-sheet content. The aggregation of both proteins occurs by misfolding of the monomers and proceeds through the formation of intermediate oligomeric and protofibrillar species to give the final fibrillar cross-β-sheet structure. The morphological and mechanical properties of oligomers, protofibrils, and fibrils formed during the fibrillization process were investigated by thioflavin T fluorescence and circular dichroism in combination with AFM peak force quantitative nanomechanical technique. The results reveal an increase in the Young’s modulus during the transformation from oligomers to mature fibrils, thus inferring that the difference in their mechanical properties is due to an internal structural change from a random coil to a structure with increased β-sheet content.

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