LAboratoire de Spectrochimie Infrarouge et Raman – UMR 8516
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Séminaire du Dr. Dominique Bourgeois

Université Joseph Fourier de Grenoble, IBS - Institut de Biologie Structurale Jean-Pierre Ebel
Phototransformable fluorescent proteins: a mechanistic view

Phototransformable fluorescent proteins (PTFPs) have received considerable attention in recent years because they enable many new exciting modalities in fluorescence microscopy and biotechnology. Upon illumination with proper actinic light, PTFPs undergo long-lived transitions between various fluorescent or nonfluorescent states, resulting in processes known as photoactivation, photoconversion or photoswitching. These processes come in addition to stochastic photoblinking and irreversible photobleaching, which universally characterize fluorescent molecules. The highly complex photophysical behavior of PTFPs can be investigated at the molecular scale by a combination of X-ray crystallography, in crystallo optical spectroscopy (UV-vis absorbance, fluorescence and Raman), mass spectrometry and simulation methods such as quantum-chemistry/molecular-mechanics hybrid approaches. In this way, it is possible to decipher the subtle conformational dynamics driving phototransformations in PTFPs, eventually facilitating the rational engineering of better performing markers for advanced nanoscopy or biotechnological applications. Based on our studies of IrisFP (1-5), a fascinating PTFP which exhibits combined green-to-red irreversible photoconversion and on-off reversible photoswitching in both its green and red states, we will detail how structural dynamics in PTFPs control their complex photophysics.

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[2] V. Adam, P. Carpentier, S. Violot, M. Lelimousin, C. Darnault, G.U. Nienhaus, D. Bourgeois J. Am. Chem. Soc., 2009, 131 (50), 18063–18065
[3] M. Lelimousin, V. Adam, G.U. Nienhaus, D. Bourgeois, M.J. Field J. Am. Chem. Soc., 2009, 131 (46), 16814–16823
[4] A. Roy, M. Field, V. Adam, D. Bourgeois J. Am. Chem. Soc., 2011, 133, 18586–18589
[5] D. Bourgeois, V. Adam IUBMB Life, 2012, 64, 482-491
The seminar will be held on 19.06.2013 at 10h30
LASIR meeting room, basement building C5