The far UV CD spectrum of rNSs protein was recorded using a Jasco-815 spectropolarimeter. The ellipticity was monitored at 25uC from 200 nm to 250 nm using 0.2 mg/ml of the purified protein in 20 mM Tris-HCl pH 8.0 and 100 mM NaCl. A scan speed of 50 nm/min, 0.2 cm path length cuvette, band width of 1 nm and response time of 1 s were used. The average of three spectra was taken and corrected with buffer blanks. The molar ellipticity was calculated using the software provided by the manufacturer.