Comparison of biophysical properties of s-GFP, n-GFP and variants.

[a]The relative fluorescence (in arbitrary units) is defined as the whole cell fluorescence compared with fluorescence of cells expressing s-GFP. All the fluorescence values were normalized by the O.D600 nm of expressed cells.[b]Specific activity (in arbitrary units/µM of purified protein) is the fluorescence of purified protein compared with the fluorescence of purified protein of s-GFP.[c]The excitation and emission maxima in units of nanometers.[d]The refolding rate constant for the fast phase calculated by fitting refolding curve in sigma plot.[e]Concentration of urea (M) at which 50% of the initial fluorescence is recovered during refolding of urea denatured protein.