title: Solution conditions define morphological homogeneity of α-synuclein fibrils.
abstract: The intrinsically disordered human α-synuclein (αSyn) protein exhibits considerable heterogeneity in in vitro fibrillization reactions. Using atomic force microscopy (AFM) we show that depending on the solvent conditions, A140C mutant and wild-type αSyn can be directed to reproducibly form homogeneous populations of fibrils exhibiting regular periodicity. Results from Thioflavin-T fluorescence assays, determination of residual monomer concentrations and native polyacrylamide gel electrophoresis reveal that solvent conditions including EDTA facilitate incorporation of a larger fraction of monomers into fibrils. The fibrils formed in 10mM Tris-HCl, 10mM NaCl and 0.1mM EDTA at pH7.4 display a narrow distribution of periodicities with an average value of 102±6nm for the A140C mutant and 107±9nm for wt αSyn. The ability to produce a homogeneous fibril population can be instrumental in understanding the detailed structural features of fibrils and the fibril assembly process. Moreover, the availability of morphologically well-defined fibrils will enhance the potential for use of amyloids as biological nanomaterials.
authors.affiliation: Nanobiophysics, MESA+Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Arshdeep
authors.initials: A
authors.lastname: Sidhu
authors.affiliation: Nanobiophysics, MESA+Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors.forename: Ine
authors.initials: I
authors.lastname: Segers-Nolten
authors.affiliation: Nanobiophysics, MESA+Institute for Nanotechnology, University of Twente, Enschede, The Netherlands; MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands; FOM Institute AMOLF, Amsterdam, The Netherlands. Electronic address: subramaniam@amolf.nl.
authors.forename: Vinod
authors.initials: V
authors.lastname: Subramaniam
keywords: Fibrillization; Homogeneous; Morphology; Periodicity; α-Synuclein