title: Molecular Rotors Provide Insights into Microscopic Structural Changes During Protein Aggregation.
abstract: Changes in microscopic viscosity represent an important characteristic of structural transitions in soft matter systems. Here we demonstrate the use of molecular rotors to explore the changes in microrheology accompanying the transition of proteins from their soluble states into a gel phase composed of amyloid fibrils. The formation of beta-sheet rich protein aggregates, including amyloid fibrils, is a hallmark of a number of neurodegenerative disorders, and as such, the mechanistic details of this process are actively sought after. In our experiments, molecular rotors report an increase in rigidity of approximately three orders of magnitude during the aggregation reaction. Moreover, phasor analysis of the fluorescence decay signal from the molecular rotors suggests the presence of multiple distinct mechanistic stages during the aggregation process. Our results show that molecular rotors can reveal key microrheological features of protein systems not observable through classical fluorescent probes operating in light switch mode.
authors.affiliation: †Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Thompson
authors.affiliation: ‡Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
authors.forename: Therese W
authors.initials: TW
authors.lastname: Herling
authors.affiliation: †Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
authors.forename: Markéta
authors.initials: M
authors.lastname: Kubánková
authors.affiliation: †Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
authors.forename: Aurimas
authors.initials: A
authors.lastname: Vyšniauskas
authors.affiliation: ‡Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
authors.forename: Tuomas P J
authors.initials: TP
authors.lastname: Knowles
authors.affiliation: †Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
authors.forename: Marina K
authors.initials: MK
authors.lastname: Kuimova
mesh_terms: D000682:Amyloid / Q000737:chemistry; D000818:Animals; D052160:Benzothiazoles / Q000737:chemistry*; D002232:Carbocyanines / Q000737:chemistry*; D002417:Cattle; D002645:Chickens; D004527:Egg Proteins / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D007328:Insulin / Q000737:chemistry*; D044085:Microfluidics; D036641:Microscopy, Fluorescence, Multiphoton; D009113:Muramidase / Q000737:chemistry*; D044367:Phase Transition; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry; D014783:Viscosity
chemical_list: D000682:Amyloid; D052160:Benzothiazoles; D002232:Carbocyanines; D004527:Egg Proteins; D005782:Gels; D007328:Insulin; D012996:Solutions; D013844:Thiazoles; C009462:thioflavin T; C072030:3,3'-diethylthiacarbocyanine iodide; D009113:Muramidase