Seminarium Zakładu Biofizyki

Fluorescent proteins (FPs) are nowadays widely used in a variety of spectroscopic methods, especially as biological markers for in vitro and in vivo imaging. One of the interesting applications is monitoring changes in the anisotropy of the green fluorescent protein (GFP) fluorescence in cells and tissues.We performed comparative studies on EGFP (F64L/S65T-GFP) fluorescence properties in different environment – from various solutions to molecule entrapped in the polyvinyl alcohol (PVA) film. In contrast to small organic fluorescent molecules stiffened in polymer matrices, the immobilisation of EGFP in the PVA film results in a shorter fluorescence lifetime and rotational correlation time, as well as lower initial anisotropy (R0). Interestingly, increasing the viscosity of the solution does not affect any of EGFP fluorescence properties.We suggest that the fast anisotropy decay in PVA film is due to an increase in the mobility of the EGFP chromophore inside the protein after rearrangement of hydrogen bonds during PVA drying.These findings shed light on the role and importance of structural water in GFP. The revealed unique fluorescent properties of GFP may be used to the development of novel applications in its use as a molecular marker.