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Formation of α‐synuclein aggregates in aqueous ethylammonium nitrate solutions
Author(s) -
Takekiyo Takahiro,
Yamada Natsuki,
Nakazawa Chikako T.,
Amo Taku,
Asano Atsushi,
Yoshimura Yukihiro
Publication year - 2020
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.23352
Subject(s) - chemistry , polyproline helix , aqueous solution , intermolecular force , molecule , side chain , raman spectroscopy , crystallography , helix (gastropod) , polymer , organic chemistry , peptide , ecology , snail , biology , biochemistry , physics , optics
The effect of adding ethylammonium nitrate (EAN), which is an ionic liquid (IL), on the aggregate formation of α‐synuclein (α‐Syn) in aqueous solution has been investigated. FTIR and Raman spectroscopy were used to investigate changes in the secondary structure of α‐Syn and in the states of water molecules and EAN. The results presented here show that the addition of EAN to α‐Syn causes the formation of an intermolecular β‐sheet structure in the following manner: native disordered state → polyproline II (PPII)‐helix → intermolecular β‐sheet (α‐Syn amyloid‐like aggregates: α‐SynA). Although cations and anions of EAN play roles in masking the charged side chains and PPII‐helix‐forming ability involved in the formation of α‐SynA, water molecules are not directly related to its formation. We conclude that EAN‐induced α‐Syn amyloid‐like aggregates form at hydrophobic associations in the middle of the molecules after masking the charged side chains at the N‐ and C‐terminals of α‐Syn.