title: The First Step of Amyloidogenic Aggregation.
abstract: The structural and dynamic characterization of the on-pathway intermediates involved in the mechanism of amyloid fibril formation is one of the major remaining biomedical challenges of our time. In addition to mature fibrils, various oligomeric structures are implicated in both the rate-limiting step of the nucleation process and the neuronal toxicity of amyloid deposition. Single-molecule fluorescence spectroscopy (SMFS) is an excellent tool for extracting most of the relevant information on these molecular systems, especially advanced multiparameter approaches, such as pulsed interleaved excitation (PIE). In our investigations of an amyloidogenic SH3 domain of α-spectrin, we have found dynamic oligomerization, even prior to incubation. Our single-molecule PIE experiments revealed that these species are small, mostly dimeric, and exhibit a loose and dynamic molecular organization. Furthermore, these experiments have allowed us to obtain quantitative information regarding the oligomer stability. These pre-amyloidogenic oligomers may potentially serve as the first target for fibrillization-prevention strategies.
authors.affiliation: †Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071 Granada, Spain.
authors.forename: Fabio
authors.initials: F
authors.lastname: Castello
authors.affiliation: ‡Department of Physical Chemistry, Faculty of Sciences, University of Granada, Campus Fuentenueva, 18071 Granada, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Casares
authors.affiliation: †Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071 Granada, Spain.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Ruedas-Rama
authors.affiliation: †Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071 Granada, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Orte
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D006863:Hydrogen-Ion Concentration; D008856:Microscopy, Fluorescence / Q000379:methods; D009154:Mutation; D055503:Protein Multimerization; D013049:Spectrin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods*; D018909:src Homology Domains
chemical_list: D000682:Amyloid; D013049:Spectrin