Figure 6: Effect of α-PrP concentrations on the emission spectra of YOYO (8 nM) intercalated in 27-mer oligonucleotide (400 nM in phosphate). Spectrum (1), fluorescence spectra of the YOYO bound to the oligonucleotide in Hepes buffer, pH 7.4 containing 100 mM NaCl in the absence of α-PrP; traces (2) and (3) are the fluorescence spectra of the dye after the addition of the protein (final concentrations 0.6 and 1.2 μM, resp.) to the oligonucleotides. Dye 8 nM and DNA-phosphate 400 nM (ratio 1 : 50). Excitation 485 nm. Temperature 20°C.