Small unilamellar vesicles (SUVs) were prepared according to the following process. The lipid mixture (palmitoyloleoyl phosphatidylethanolamine, POPE; palmitoyloleoyl phosphatidyl-glycerol, POPG) POPE/POPG (7:3) was dissolved in chloroform and dried under N2 overnight in a glass tube. The dried lipid powder was resuspended in 1× PBS buffer (pH 7.4) at room temperature. The resulting multi-lamellar vesicle suspension was press-filtered through a liquid extruder (Northern Lipids) equipped with a 0.1-μm pore size Whatman Nuclepore hydrophilic membrane to produce homogeneous liposomes (SUVs), which were used within 6 h of production.
CD spectra were recorded on a Chirascan Circular Dichroism Spectrometer. The AP1-Z1 and its six mutants (AP1-Z3a, AP1-Z3b, AP1-Z5a, AP1-Z5b, AP1-Z7, and AP1-Z9) were dissolved in 1× PBS, pH 7.4 at a concentration of 0.5 mM, and the negative control was treated with equal volumes of PBS. Spectra were run at 25°C from 250 to 190 nm using a quartz cell that was 0.1 mm in length. Data were collected at 1-nm intervals at a scan rate of 60 nm/min. All CD spectra were the average of three scans, and the final spectrum was corrected by subtracting the corresponding baseline spectrum obtained under identical conditions. The secondary structure content was estimated by CDNN 2.1 standard analysis.
CD spectra were recorded on a Chirascan Circular Dichroism Spectrometer. The AP1-Z1 and its six mutants (AP1-Z3a, AP1-Z3b, AP1-Z5a, AP1-Z5b, AP1-Z7, and AP1-Z9) were dissolved in 1× PBS, pH 7.4 at a concentration of 0.5 mM, and the negative control was treated with equal volumes of PBS. Spectra were run at 25°C from 250 to 190 nm using a quartz cell that was 0.1 mm in length. Data were collected at 1-nm intervals at a scan rate of 60 nm/min. All CD spectra were the average of three scans, and the final spectrum was corrected by subtracting the corresponding baseline spectrum obtained under identical conditions. The secondary structure content was estimated by CDNN 2.1 standard analysis.