Intermolecular crosslinking of abnormal prion protein is efficiently induced by a primuline-sensitized photoreaction |
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Authors: | Kenta Teruya Keiko Nishizawa Ayumi Oguma Yuji Sakasegawa Tetsuyuki Kitamoto Katsumi Doh-ura |
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Institution: | 1. Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan;2. Department of Neurological Science, Tohoku University Graduate School of Medicine, Sendai, Japan |
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Abstract: | In prion diseases, infectious pathogenic particles that are composed of abnormal prion proteins (PrPSc) accumulate in the brain. PrPSc is biochemically characterized by its protease-resistance core (PrPres), but its structural features have not been fully elucidated. Here, we report that primuline, a fluorescent dye with photosensitization activity, dramatically enhances UV-irradiation-induced SDS-resistant PrPSc/res oligomer formation that can be detected by immunoblot analysis of prion-infected materials. This oligomer formation occurs specifically with PrPSc/res but not with normal prion protein, and it was demonstrated using purified PrPSc/res as well as unpurified materials. The oligomer formation proceeded in both primuline-dose- and UV irradiation time-dependent manners. Treatment with urea or formic acid did not break oligomers into monomers. Neither did the presence of aromatic amino acids modify oligomer formation. Analysis with a panel of anti-prion protein antibodies showed that the antibodies against the N-terminal region of PrPres were less reactive in the dimer than the monomer. These findings suggest that the primuline-sensitized photoreaction enhances intermolecular crosslinking of PrPSc/res molecules at a hydrophobic area of the N-terminal region of PrPres. In the screening of other compounds, photoreactive compounds such as luciferin exhibited a similar but lower activity with respect to oligomer formation than primuline. The enhanced photoreaction with these compounds will be useful for evaluating the structural features of PrPSc/res, especially the interactions between PrPSc/res molecules. |
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Keywords: | Prion Oligomer Interface Crosslinking Fibril Amyloid CR Congo red MB methylene blue N2a Neuro-2a PK proteinase K PL primuline PrP prion protein C normal cellular PrP Sc abnormal PrP res Sc PTA phosphotungstic acid |
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