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"Mechanism and applications of photo- and redox-switchable fluorescent proteins"

Relatore: S. James Remington- Institute of Molecular Biology and Dept. of Physics, University of Oregon, Eugene, Oregon, United States

Aula A plesso polifunzionale del campus
28 Maggio 2008 ore 11.00

Photoswitchable fluorescent proteins have significant advantages over conventional fluorescent labels, and in a revolutionary application, now allow cell biologists to exceed the diffraction limit in light microscopy by a factor of ten. We have determined high resolution crystal structures of a reversible fluorescent protein photoswitch (mTFP0.7) in both the light emitting and dark states. The effort has led to a detailed atomic mechanism that explains the long term stability of both the light and dark states, as well as how illumination at the appropriate wavelength causes the molecule to switch between states. The results of directed mutagenesis combined with time resolved spectroscopy support the proposed mechanism and give new insight into the metastability of the light and dark states. The photoswitching mechanism will be discussed in terms of light induced chromophore isomerization and excited state proton transfer (ESPT). I will also briefly discuss how an understanding of ESPT aids in the development and application of redox-sensitive GFP biosensors.