Fig. 4

Near-UV CD and FS spectra of the mRBD and dRBD. Lots of the RBD are shown: mRBD Lot 1 (black), mRBD Lot 2 (red), dRBD Lot 1 (blue) and dRBD Lot 2 (pink). A Near-UV CD spectra, where each spectrum is the average of 3 scans in the 250–350 nm range, with 41.35 µmol/l of mRBD and 20.67 µmol/l of dRBD, in quartz cuvettes of 1 cm of light path. The mean residual ellipticity readings (deg.cm².dmol⁻¹) for each wavelength were performed on a Jasco J-1500 spectropolarimeter (Jasco Corporation, Japan) at 25 °C; 0.1 nm of intervals and constant speed of 10 nm/min with 16 s of response time. The spectra were filtered with the FFT in a 20-point window to smooth out the curve in the Origin-v15.0 program (Origin Lab Corporation, USA). B FS spectra, where each spectrum represents the fluorescence emission intensity (a.u) for each wavelength (nm) and is the product of a single scan in the 307–410 nm range. Selective Trp excitation was performed at 295 nm, with 5 nm slits for excitation and emission, respectively. Protein concentration 4.13 µmol/l of mRBD and 2.07 µmol/l of dRBD. Spectra were acquired using a Jasco J-1500 spectropolarimeter (Jasco Corporation, Japan), in quartz cuvettes with a 1 cm light path, at 25 °C