Chirascan plus spectropolarimeter v 4

For CD analysis, peptide samples were dissolved in 5 mM phosphate buffer (pH 7.0) and RBD was in 50 mM sodium phosphate buffer (pH 7.0) containing 150 mM NaCl, with a concentration of 0.1–0.2 mg/mL. CD spectra were measured on the Chirascan Plus spectropolarimeter v.4.4.0 (Applied Photophysics Ltd., Leatherhead, Surrey, UK) by using a quartz cell of 1.0 mm thickness. The wavelengths used ranged from 190 to 260 nm. Data were collected at 1 nm intervals with a scan rate of 60 nm/min and expressed as delta epsilon (cm⁻¹M⁻¹). Delta epsilon was calculated as [θ × (MRW × 0.1)/(C × L)/3298], where θ is the ellipticity (in millidegrees), C is the concentration (in mg/mL), L is the path length (in cm), and MRW is the mean residue weight (in Da).

Structural features of recombinant peptides were studied by circular dichroism (CD) spectroscopy analysis on Chirascan Plus spectropolarimeter v.4.4.0 (Applied Photophysics Ltd., UK) (Gao and Zhu, 2016 (link)). Spectra were recorded at 10–65°C with a quartz cell of 1.0 mm thickness with a peptide concentration of 0.1 mg/ml in water. The wavelengths used ranged from 185 to 260 nm. Data were collected at 1 nm intervals with a scan rate of 60 nm/min and expressed as delta epsilon (cm^–1M^–1) calculated as [θ × (MRW × 0.1)/(C × L)/3298], where θ is the ellipticity (in millidegrees), C is the concentration (in mg/ml), L is the pathlength (in cm), and MRW is the mean residue weight (in Da).

For CD analysis, a peptide sample was dissolved in 5 mM phosphate buffer (PB, pH7.0) with a concentration of 0.1–0.2 mg/mL. CD spectra were measured on the Chirascan Plus spectropolarimeter v.4.4.0 (Applied Photophysics Ltd, UK) by using a quartz cell of 1.0 mm thickness. The wavelengths used ranged from 190 to 260 nm. Data were collected at 1 nm intervals with a scan rate of 0.5 s per point and expressed as delta epsilon (cm^-1M^-1). Delta epsilon was calculated as [θ×(MRW×0.1)/(C×L)/3298], where θ is the ellipticity (in millidegrees), C is the concentration (in mg/mL), L is the path length (in cm), and MRW is the mean residue weight (in Da).