2.3. Circular Dichroism (CD) Spectroscopy

The α-helical structures of the peptides were investigated using a J-810 spectrometer (Jasco, Tokyo, Japan). Peptides (100 μg/mL) were dissolved in 50% trifluoroethanol (TFE) to mimic a hydrophobic membrane environment and 0.01-M PBS to mimic an aqueous environment [13]. The spectral wavelengths ranged from 190 to 260 nm. The other parameters were as follows: 50-nm/min scanning rate, 1-nm bandwidth and a 1-s response.