Spectral properties of the αS-EGFP construct. (A) Absorbance spectra of αS-EGFP (dashed lines) and EGFP (solid lines). Spectra are shown for 5 μM protein in 10 mM phosphoric acid (pH 2.4, red lines) and 10 mM NaPhos buffer (pH 7.5, black lines). (B) The normalized fluorescence emission from αS-EGFP (squares) and EGFP (circles) as a function of TFE concentration. The signal from 0.3 μM protein is measured after a 2.0 ± 0.5 minute incubation at 22°C (cyan symbols), after 2.0 ± 0.5 minutes at 37°C (red symbols), and after 24 ± 2 hours at 37°C (yellow symbols). The error bars reflect the standard deviations of measurements of three identical samples and baseline uncertainties.