title: A rationally designed six-residue swap generates comparability in the aggregation behavior of α-synuclein and β-synuclein.
abstract: The aggregation process of α-synuclein, a protein closely associated with Parkinson's disease, is highly sensitive to sequence variations. It is therefore of great importance to understand the factors that define the aggregation propensity of specific mutational variants as well as their toxic behavior in the cellular environment. In this context, we investigated the extent to which the aggregation behavior of α-synuclein can be altered to resemble that of β-synuclein, an aggregation-resistant homologue of α-synuclein not associated with disease, by swapping residues between the two proteins. Because of the vast number of possible swaps, we have applied a rational design procedure to single out a mutational variant, called α2β, in which two short stretches of the sequence in the NAC region have been replaced in α-synuclein from β-synuclein. We find not only  that the aggregation rate of α2β is close to that of β-synuclein, being much lower than that of α-synuclein, but also that α2β effectively changes the cellular toxicity of α-synuclein to a value similar to that of β-synuclein upon exposure of SH-SY5Y cells to preformed oligomers. Remarkably, control experiments on the corresponding mutational variant of β-synuclein, called β2α, confirmed that the mutations that we have identified also shift the aggregation behavior of this protein toward that of α-synuclein. These results demonstrate that it is becoming possible to control in quantitative detail the sequence code that defines the aggregation behavior and toxicity of α-synuclein.
authors.affiliation: CABIMER-Andalusian Center for Molecular Biology & Regenerative Medicine, CSIC-University of Seville-UPO-Junta de Andalucía, Seville, Spain.
authors.forename: Cintia
authors.initials: C
authors.lastname: Roodveldt
authors.forename: August
authors.initials: A
authors.lastname: Andersson
authors.forename: Erwin J
authors.initials: EJ
authors.lastname: De Genst
authors.forename: Adahir
authors.initials: A
authors.lastname: Labrador-Garrido
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Buell
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dobson
authors.forename: Gian Gaetano
authors.initials: GG
authors.lastname: Tartaglia
authors.forename: Michele
authors.initials: M
authors.lastname: Vendruscolo
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002470:Cell Survival; D006801:Humans; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D016415:Sequence Alignment; D014407:Tumor Cells, Cultured; D051844:alpha-Synuclein / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity; D051846:beta-Synuclein / Q000737:chemistry* / Q000633:toxicity
chemical_list: D051844:alpha-Synuclein; D051846:beta-Synuclein