Open AccessSelf‐oligomerization and protein aggregation of α‐synuclein in the presence of Coomassie Brilliant Blue
Author(s) -
Lee Daekyun,
Lee EunKyung,
Lee JuHyun,
Chang ChungSoon,
Paik Seung R.
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2001.01877.x
Subject(s) - alpha synuclein , coomassie brilliant blue , chemistry , protein aggregation , neurodegeneration , biophysics , reagent , dissociation (chemistry) , biochemistry , stereochemistry , organic chemistry , staining , biology , parkinson's disease , pathology , medicine , disease , genetics
α‐Synuclein has been implicated in various neurodegenerative disorders, including Parkinson's and Alzheimer's diseases, by its participation in abnormal protein depositions. As the protein has been suggested to play a significant role in the formation of the deposits which might be responsible for neurodegeneration, there is a strong demand to screen for α‐synuclein‐interactive small molecules. In this report, Coomassie Brilliant Blue (CBB) interaction of α‐synuclein has been investigated with respect to induction of protein self‐oligomerization in the presence of the chemical coupling reagent N ‐(ethoxycarbonyl)‐2‐ethoxy‐1,2‐dihydroquinoline. Both CBB‐G and CBB‐R, which differ by only two methyl groups, induced the self‐oligomerization of α‐synuclein in a biphasic manner with optimal dye concentrations of 250 µ m and 150 µ m , respectively. The protein aggregates of α‐synuclein induced by the dyes in the absence of the coupling reagent were analysed by electron microscopy. Whereas CBB‐G induced formation of protein aggregates with a worm‐like structure, CBB‐R induced clear fibrilization of α‐synuclein on a background of granular structures. CBB‐R interacted with α‐synuclein approximately twice as effectively as CBB‐G (dissociation constants 0.63 µ m and 1.37 µ m , respectively). These dye interactions were independent from the acidic C‐terminus of α‐synuclein, which was reminiscent of the Αβ25–35 interaction of α‐synuclein. However, the metal‐catalysed oxidative self‐oligomerization of α‐synuclein in the presence of Cu 2+ /H 2 O 2 , which was augmented synergistically by Αβ25–35, was not affected by the dyes. This indicates that the dye binding site is also distinctive from the Αβ25–35 interaction site on α‐synuclein. These biochemically specific interactions between α‐synuclein and the dyes indicate that α‐synuclein‐interactive small molecules could provide a tool with which to approach development of diagnostic, preventive, or therapeutic strategies for various α‐synuclein‐related neurodegenerative disorders.