Effect of high pressure and reversed micelles on the fluorescent proteins.

Two physico-chemical perturbations were applied to ECFP, EGFP, EYFP and DsRed fluorescent proteins: high hydrostatic pressure and encapsulation in reversed micelles. The observed fluorescence changes were described by two-state model and quantified by thermodynamic formalism. ECFP, EYFP and DsRed exhibited similar reaction volumes under pressure. The changes of the chemical potentials of the chromophore in bis(2-ethylhexyl)sulfosuccinate (AOT) micelles caused apparent chromophore protonation changes resulting in a fluorescence decrease of ECFP and EYFP. In contrast to the remarkable stability of DsRed, the highest sensitivity of EYFP fluorescence under pressure and in micelles is attributed to its chromophore structure.