Figure 3.

Graphical representation of the melting temperatures defined by the thermal shift assay. A. A selection of thermal shift assay melting curves for the CNPase catalytic domain in pH 5.5 (0 mM NaCl, blue; 500 mM NaCl, red) and 7.5 (0 mM NaCl, green; 500 mM NaCl, purple). A clear increase in the melting temperature can be seen from the graphs, induced by both pH 5.5 and high salt concentration. B. The stability of the C-terminal domain in different conditions as a function of pH. Black, 150 mM NaCl; red, 500 mM NaCl; blue, 10% glycerol; green, 5% PEG400. C. The effect of different salts on the stability of the full-length protein (construct 4-1). Blue, sodium acetate; red, lithium sulfate; black, ammonium sulfate; green, sodium phosphate; orange, sodium citrate. The buffer in the experiment was 50 mM Bis-Tris, pH 5.5. D. A comparison between ammonium sulfate (circles) and sodium chloride (squares). See Additional File 3 for more details on the thermal shift assays.