Effect of pH on the stability of the GFP variants.

A) Protein samples were incubated at 60°C for 30 minutes in different pH buffer solutions and the remaining fluorescence was measured. The fluorescence at time zero at the respective buffer was taken into 100%. B) Protein samples in KCl buffer with pH 13.0 were incubated at 60°C for different time intervals and the remaining fluorescence was measured. The fluorescence at time zero was taken into 100%. (Error bar – Standard deviation of the three independent experiments).