title: Dimerization of Tyr136Cys alpha-synuclein prevents amyloid transformation of wild type alpha-synuclein.
abstract: Expression of human alpha-synuclein in E. coli cells is known to result in a mixture of the wild type alpha-synuclein and the protein containing Tyr136Cys substitution due to the translational error. The amount of Cys136 alpha-synuclein (Cys136-AS) may reach approximately 50% of the recombinant protein. The wild-type and Cys136-containing fractions of alpha-synuclein were separated using thiol-Sepharose, and their properties were investigated. In the absence of reducing agents, Cys136-AS forms dimers due to the disulfide bonding. Both wild-type and Cys136 alpha-synuclein preparations are prone to aggregate during prolonged incubation under shaking at pH 4 and 37°C, but only the wild-type alpha-synuclein produces amyloid aggregates. The aggregates produced by either monomeric or dimeric Cys136-AS do not exhibit amyloid properties according to the test with Thioflavin T. Moreover, an admixture of dimeric Cys136-AS prevents the amyloid transformation of the wild-type alpha-synuclein. CD spectroscopy analysis revealed an enhanced content of alpha-helical structures in the aggregates produced by dimeric Cys136-AS. The admixture of Cys136-AS in preparations of human recombinant alpha-synuclein can be a source of erroneous interpretation of experiments on amyloid transformation of this protein.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia.
authors.forename: K V
authors.initials: KV
authors.lastname: Barinova
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
authors.forename: M L
authors.initials: ML
authors.lastname: Kuravsky
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
authors.forename: A M
authors.initials: AM
authors.lastname: Arutyunyan
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
authors.forename: M V
authors.initials: MV
authors.lastname: Serebryakova
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Schmalhausen
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia. Electronic address: vimuronets@belozersky.msu.ru.
authors.forename: V I
authors.initials: VI
authors.lastname: Muronetz
mesh_terms: D019943:Amino Acid Substitution; D000682:Amyloid / Q000737:chemistry*; D045744:Cell Line, Tumor; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D008745:Methylation; D066329:Protein Aggregates / Q000235:genetics*; D055503:Protein Multimerization / Q000235:genetics*; D017433:Protein Structure, Secondary; D051844:alpha-Synuclein / Q000737:chemistry* / Q000235:genetics*
chemical_list: D000682:Amyloid; D066329:Protein Aggregates; D051844:alpha-Synuclein
keywords: Aggregation; Alpha-synuclein; Amyloid transformation; Misincorporation