RESUMO
The prion protein (PrP) misfolding to its infectious form is critical to the development of prion diseases, whereby various ligands are suggested to participate, such as copper and nucleic acids (NA). The PrP globular domain was shown to undergo NA-driven liquid-liquid phase separation (LLPS); this latter may precede pathological aggregation. Since Cu(II) is a physiological ligand of PrP, we argue whether it modulates phase separation altogether with nucleic acids. Using recombinant PrP, we investigate the effects of Cu(II) (at 6 M equivalents) and a previously described PrP-binding GC-rich DNA (equimolarly to protein) on PrP conformation, oligomerization, and phase transitions using a range of biophysical techniques. Raman spectroscopy data reveals the formation of the ternary complex. Microscopy suggests that phase separation is mainly driven by DNA, whereas Cu(II) has no influence. Our results show that DNA can be an adjuvant, leading to the structural conversion of PrP, even in the presence of an endogenous ligand, copper. These results provide new insights into the role of Cu(II) and NA on the phase separation, structural conversion, and aggregation of PrP, which are critical events leading to neurodegeneration.
Assuntos
Cobre/química , Oligonucleotídeos/química , Proteínas da Gravidez/química , Agregados Proteicos , Animais , Cátions Bivalentes , Clonagem Molecular , Cobre/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Camundongos , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Proteínas da Gravidez/genética , Proteínas da Gravidez/metabolismo , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
Transmissible spongiform encephalopathies form a group of neurodegenerative diseases that affect humans and other mammals. They occur when the native prion protein is converted into an infectious isoform, the scrapie PrP, which aggregates, leading to neurodegeneration. Although several compounds were evaluated for their ability to inhibit this conversion, there is no effective therapy for such diseases. Previous studies have shown that antimalarial compounds, such as quinolines, possess anti-scrapie activity. Here, we report the synthesis and evaluate the effect of aminoquinoline derivatives on the aggregation of a prion peptide. Our results show that 4-amino-7-chloroquinoline and N-(7-chloro-4-quinolinyl)-1,2-ethanediamine inhibit the aggregation significantly. Therefore, such aminoquinolines might be considered as candidates for the further development of therapeutics to prevent the development of prion diseases.