Structural Perturbation of Superfolder GFP in the Presence of Guanidine Thiocyanate

The guanidine-thiocyanate-induced denaturation-renaturation of sfGFP was studied. It was shown that the disruption of sfGFP native structure occurs in the range of guanidine thiocyanate concentrations from 0.5 to 2.5 M. This process was accompanied by simultaneous changes of all recorded parameters. It was found that the small guanidine thiocyanate concentrations (less then 0.1-0.2 M) triggered local structural disturbances in protein which result in significant decrease of chromophore and tryptophan fluorescence intensity and change of protein visible absorption spectrum.