title: Macromolecular crowding converts the human recombinant PrPC to the soluble neurotoxic beta-oligomers.
abstract: Prion diseases are fatal neurodegenerative disorders and are linked with the conversion of the cellular isoform of the prion protein (PrP(C)) into the abnormal beta-sheet-rich isoform. It is widely accepted that the soluble oligomers of beta-PrP are neurotoxic and that they are more pathologically significant. To unravel the molecular mechanism under the conversion process, it is critical to identify the factors that can promote the conversion from PrP(C) to the beta-oligomers. By recording circular dichroism spectra and performing a size-exclusion HPLC assay, we found that the conformation of the recombinant human prion protein (rPrP(C)) was converted from an alpha-helical conformation into beta-sheet oligomers under a macromolecular crowding condition. The soluble beta-oligomers of rPrP were resistant to proteinase K digestion and could bind to the dyes thioflavin T and 8-anilino-1-naphthalene sulfonate. Furthermore, by the 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, we showed that the soluble beta-oligomers were neurotoxic. These results suggest that macromolecular crowding, which has not been considered before, is a key intracellular factor in the formation of soluble neurotoxic beta-oligomers in prion diseases.
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Liqin
authors.initials: L
authors.lastname: Huang
authors.forename: Rui
authors.initials: R
authors.lastname: Jin
authors.forename: Jiarui
authors.initials: J
authors.lastname: Li
authors.forename: Kan
authors.initials: K
authors.lastname: Luo
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Wenxi
authors.initials: W
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.forename: Gengfu
authors.initials: G
authors.lastname: Xiao
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D006801:Humans; D018621:PrPC Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D013816:Thermodynamics
chemical_list: D018621:PrPC Proteins; D011994:Recombinant Proteins