Figure 9.

Thermodynamic stability of OsINO1, PcINO1, and the mutant proteins in absence and presence of NaCl. Urea-induced denaturation profile of PcINO1 (A), OsINO1 (B), ΔPcINO1.2 (C), and Os∷PcINO1 (D) in absence and presence of 500 mm NaCl at 25°C. All the experiments were done at a protein concentration of 0.05 mg/mL, in 20 mm Tris-HCl (pH 7.5), 10 mm β-ME, and 5% glycerol. In each case protein samples were incubated in increasing concentration of urea (0–8 mm) either in absence or presence of 500 mm NaCl in total 1 mL reaction volume for about 16 h at room temperature 25°C. Samples were excited at 295 nm and emission was scanned between 300 to 400 nm. Ratio of fluorescence intensity at 337 nm to the same at 350 nm was plotted as function of urea concentration.