Winlab software package 4

Movement of tryptophan residues in the PCO-rHDL and SCWA-rHDL was determined from uncorrected spectra obtained on an LS55 spectrofluorometer (Perkin-Elmer, Norwalk, CT) and WinLab software package 4.00 (Perkin-Elmer) using a 1-cm path length Suprasil quartz cuvette (Fisher Scientific, Pittsburg, PA). The wavelengths of maximum fluorescence (WMF) in each rHDL were excited at 295 nm to avoid tyrosine fluorescence, and the emission spectra were scanned from 305 to 400 nm at room temperature.

The assaying technique of circular dichroism (CD) spectroscopy (J-715 Spectropolarimeter Jasco, Tokyo, Japan) was used to unravel the quantity of alpha-helices prevalent in the free and bound protein-lipid interaction states. The circular light absorption pattern was obtained from 250–190 nm at 25°C, 0.1 cm was path length, 1.0 nm was bandwidth, speed was 50 nm/min, and a 4 sec response time. The purified protein specimens were made fructose free by dialysis against TBS, self-ligation was averted by dilution of the lipid-free apolipoproteins [26 (link)] to 0.07 mg/mL and to 0.1 mg/mL of the lipid-bound apolipoprotein. Four scans were obtained and averaged.
The analysis of molar ellipticity at 222 nm revealed the content of alpha-helices. Circular dichroism spectra with ketohexose-treated apoA-I in lipid-free and lipid-bound are represented in Supplementary Figure 2.
The perusal of the wavelengths of fluorescence (WMF) particularly of the Trp residues was done by a LS55 spectrofluorometer (Perkin-Elmer, Norwalk, CT, USA) using WinLab software package 4.00 (Perkin-Elmer). The excitation wavelength was chosen to be 295 nm in order to steer clear of the interference from tyrosine fluorescence. Emissions were categorically checked from 305–400 nm.

The wavelengths of maximum fluorescence (WMF) of the tryptophan (Trp) residues in apoA-I were determined from the uncorrected spectra using an LS55 spectrofluorometer (Perkin-Elmer, Norwalk, CT, USA), as described previously [37 (link)], using WinLab software package 4.00 (Perkin-Elmer) and a 1 cm path-length Suprasil quartz cuvette (Fisher Scientific, Pittsburgh, PA, USA). The samples were excited at 295 nm to avoid tyrosine fluorescence, and the emission spectra were scanned from 305 to 400 nm at room temperature [38 (link)]. For isothermal denaturation, the effects of urea addition on the secondary structures of Aβ and apoA-I in a lipid-bound state were monitored by measuring the α-helicity and tryptophan movement using CD and fluorospectroscopy, as reported elsewhere [36 (link),37 (link),38 (link)].