Fig. 3

Fluorescence interaction studies between MR100 and PrP. a Fluorescence studies of MR100 compound incubated with purified recombinant MoPrP(23-230) proteins. 4 μM of MoPrP(23-230), either soluble or fibrillar, were incubated with 50 μM of MR100 in 1 % DMSO, 50 mM MES buffer pH6, during 2 h at 25 °C. Emission spectra between 400 and 550 nm were recorded by exciting at 470 nm: 50 μM of MR100 (black), 50 μM of MR100 + α-soluble MoPrP(23-230) (red), 50 μM of MR100 + fibrils of MoPrP(23-230) (green). b-c Fluorescence of tryptophan and tyrosine residues of soluble MoPrP(23-230) alone (black), or incubated with 1 % DMSO, 50 mM MES buffer pH6, during 2 h at 37 °C (red) (b). Fluorescence of tryptophan and tyrosine residues of soluble MoPrP(23-230) alone (black), or incubated with 50 μM of MR100 in 1 % DMSO, 50 mM MES buffer pH 6, during 2 h at 37 °C (red) (c). All spectra were recorded at 290 nm. d Hamster-S or -R fibrils at a concentration of 4 μM were incubated with solvent alone (1 % DMSO, 50 mM MES buffer pH6), or 40 μM of P30, A6, or MR100 compounds in 1 % DMSO, 50 mM MES buffer pH6, during 2 h at 25 °C. Samples were then mixed with loading buffer, boiled for 15 min at 90 °C and loaded on a 12 % SDS-PAGE gel. Proteins in the gel were revealed by silver staining. Molecular weight markers indicated: 27, 42 and 66 kDa. Asterisks showed dimer and trimer bands that are increased following incubation with MR100 compound