Ionic denaturants and salts effects on fluorescence of anionic and neutral chromophore of sfGFP.

Changes in the anionic chromophore fluorescence intensity, λex = 490 nm, λem = 510 (A) and λex = 390 nm, λem = 510 (B). Changes in direct fluorescence from neutral form, λex = 390 nm, λem = 450 nm (C). The value of fluorescence intensity was corrected for the primary inner filter effect (see “Materials and methods” section). Agents used were GTC (red circles) and GdnHCl (blue circles), NaSCN (pink circles) and NaCl (green circles). Data on fluorescence intensity of sfGFP in different pH are shown in gray circles, axis of abscissas for these data is on top.