Institut de Biologie StructuraleGrenoble / France

Rational design of a remarkably efficient cyan fluorescent protein

Researchers from the IBS (Institut de biologie structurale, CEA-CNRS-UJF) and the ESRF (European Synchrotron Radiation Facility), in collaboration with groups from the Universities of Amsterdam and Oxford, have managed to design a new cyan fluorescent protein (CFP) whose fluorescence efficiency is unmatched among this family of proteins, using a combination of structural biology and genetic engineering.
Thanks to their natural fluorescence, fluorescent proteins can be readily located and tracked in organisms. They constitute very good biochemical and biological markers and are essential for certain techniques of cell imaging. Cyan and yellow fluorescent proteins (CFP and YFP) are used in the so-called FRET technique to probe protein-protein interactions and protein conformational changes in cell signalling cascades. Unfortunately, CFPs have long suffered from a weak level of fluorescence, which contributes to obscure experimental results. Researchers from Grenoble, Oxford and Amsterdam have teamed up to understand and improve these proteins. Using the synchrotron radiation of the ESRF, the Grenoble team has uncovered subtle details of their structural dynamics, which were used to determine which part of the protein had to be modified to increase the level of fluorescence. The team in Amsterdam then used their innovative high-throughput screening technique based on fluorescence lifetime microscopy to identify improved proteins. In the end, the scientists managed to design and characterize a new CFP called mTurquoise2 whose fluorescence efficiency is unmatched for such proteins. mTurquoise2 will now allow researchers to study protein-protein interactions in live cells with an unprecedented level of sensitivity and to perform experiments whose results would have been hidden in noise before.

Communiqué de presse/Press release

Structure-guided evolution of cyan fluorescent proteins towards a quantum yield of 93%, J. Goedhart, D. von Stetten, M. Noirclerc-Savoye, M. Lelimousin, L. Joosen, M. A. Hink, L. van Weeren, T. W. Gadella Jr, and A. Royant, Nat. Commun. 2012 Mar 20;3:751