Resolution pro software

FTIR spectra were acquired on a Varian FTS-7000 infrared spectrometer (Varian) equipped with a DTGS (deuterated triglycine sulfate) detector. MoPrP^{c 23–231}, MoPrP ^23–231 oligomers and MoPrP ^23–231 fibril samples (50 µL of 2–3 mg/mL) were dried onto a CaF₂ plate under nitrogen. Spectra were acquired from 96 scans at a sensitivity of 2 and a resolution of 2 cm⁻¹. First a background scan was run with a CaF₂ plate in place and then a blank spectrum was acquired with buffer dried onto the CaF₂ plate. Spectra were smoothed with a Savitsky-Golay window of 9 points using the Varian Resolution Pro software. FTIR spectra were further processed using Origin (Version 9) to assist with spectral deconvolution and secondary structure quantification. The second derivatives of the smoothed spectra were calculated using Origin (Version 9) with 2^nd order Savitsky-Golay smoothing and a 9-point window. Before deconvolution, the baseline was subtracted from each absorbance spectrum. Absorbance spectra were then deconvoluted using Origin's multiple peak fit, employing non-linear Lorentz curve fitting by fixing the wavenumber of the peak maxima from the second derivative spectra and using a peak width of 20 cm⁻¹. The deconvoluted spectrum was then fit to multiple Gaussian curves by fixing the peak wavenumbers using the second derivative of the deconvoluted spectra and fixing the peak width to 13 cm⁻¹.

Small samples (<1 mg) of dried AD-EM, EM, and AD were each ground into a fine powder with a mortar and pestle. Dried potassium bromide (KBr, 0.1 g) was added to the powdered drug sample and ground into a fine powder. Each sample was placed in a 13 mm die and pressed with a force of 10 metric tons for 10 min. Each pellet was removed from the die and scanned in an Excaliber Series-BioRad FTS3000MX spectrometer. Then, 200 background and 400 sample scans were collected from 500–4000 cm⁻¹. Varian Resolution Pro Software was used to transform the data using ratio and transmittance transformations. A boxcar function was used to smooth out each plot.