Abstract

Photoswitchable fluorescent proteins have significant advantages over conventional fluorescent labels and most recently, their use has allowed researchers to break the diffraction limit in fluorescence microscopy by a factor of ten. We have determined high resolution crystal structures of a fully reversible fluorescent protein photoswitch in both the light and dark states. The results lead to a detailed atomic mechanism that explains the long term stability of the light and dark states as well as how illumination of the appropriate wavelength causes the molecule to switch between states. Recent advances in our understanding of the photophysics of excited state proton transfer and photoinduced isomerization will be discussed in terms of the proposed mechanism, which appears to be applicable to all photoswitchable fluorescent proteins described to date.

Reference:

Henderson et al. Structural basis for reversible photobleaching of a green fluorescent protein homologue. PNAS U S A (2007) 104, 6672-7.