title: Single fibril growth kinetics of α-synuclein.
abstract: Neurodegenerative disorders associated with protein misfolding are fatal diseases that are caused by fibrillation of endogenous proteins such as α-synuclein (α-syn) in Parkinson's disease (PD) or amyloid-β in Alzheimer's disease. Fibrils of α-syn are a major pathological hallmark of PD and certain aggregation intermediates are postulated to cause synaptic failure and cell death of dopaminergic neurons in the substantia nigra. For the development of therapeutic approaches, the mechanistic understanding of the fibrillation process is essential. Here we report real-time observation of α-syn fibril elongation on a glass surface, imaged by total internal reflection fluorescence microscopy using thioflavin T fluorescence. Fibrillation on the glass surface occurred in the same time frame and yielded fibrils of similar length as fibrillation in solution. Time-resolved imaging of fibrillation on a single fibril level indicated that α-syn fibril elongation follows a stop-and-go mechanism; that is, fibrils either extend at a homogenous growth rate or stop to grow for variable time intervals. The fibril growth kinetics were compatible with a model featuring two states, a growth state and a stop state, which were approximately isoenergetic and interconverted with rate constants of ~1.5×10(-4) s(-1). In the growth state, α-syn monomers were incorporated into the fibril with a rate constant of 8.6×10(3) M(-1) s(-1). Fibril elongation of α-syn is slow compared to other amyloidogenic proteins.
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors: Michael M
authors: MM
authors: Wördehoff
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Research Centre Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
authors: Oliver
authors: O
authors: Bannach
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors: Hamed
authors: H
authors: Shaykhalishahi
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Research Centre Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
authors: Andreas
authors: A
authors: Kulawik
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors: Stephanie
authors: S
authors: Schiefer
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Research Centre Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
authors: Dieter
authors: D
authors: Willbold
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Research Centre Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
authors: Wolfgang
authors: W
authors: Hoyer
authors: Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; Institute of Complex Systems (ICS-6), Research Centre Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
authors: Eva
authors: E
authors: Birkmann
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008856:Microscopy, Fluorescence; D010300:Parkinson Disease; D051844:alpha-Synuclein / Q000737:chemistry*
chemical_list: D000682:Amyloid; D051844:alpha-Synuclein
keywords: Parkinson's disease; amyloid; fibril formation; protein aggregation; thioflavin T