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CNR: Alamanacco della Scienza


N. 6 - 28 mar 2012
ISSN 2037-4801

International info   a cura di Cecilia Migali


Proteins shine a brighter light on cellular processes  

Scientists have designed a molecule which emits turquoise light more efficiently than seen before in living cells. This improves the sensitivity of imaging of biological processes inside a living cell. The results have been published in Nature Communications on 20 March 2012.
The lead author of the publication is Antoine Royant from the Institut de Biologie Structurale/Cnrs-Cea-Université Joseph Fourier in Grenoble. The team also comprised scientists from the Universities of Amsterdam and Oxford, and the European Synchrotron Radiation Facility (Esrf) in Grenoble.
Cyan fluorescent proteins (Cfps) are very popular in cell biology where they are used to make processes visible inside a living cell, like in a movie. These processes include the changes in the shape of large biological molecules. Since the early 1990s, fluorescent proteins have become one of the most important tools used in the biosciences and have helped the observation of previously invisible processes such as the development of nerve cells in the brain or the spread of cancer cells. The 2008 Nobel Prize in Chemistry crowned their discovery and rapid development.
To achieve higher brightness, and with it improved sensitivity of fluorescent imaging, the scientists based in France, led by Antoine Royant, teamed up with colleagues from the Netherlands and the United Kingdom. First, using highly brilliant X-ray beams at the Esrf, the teams from Grenoble and Oxford uncovered subtle details of how Cfps store incoming energy and retransmit it as fluorescent light: they produced tiny crystals of many different improved Cfps and resolved their molecular structures. These structures revealed a subtle process near the so-called chromophore, the light-emitting complex inside the Cfps, whose fluorescence efficiency could be modulated by the environment. "We could understand the function of individual atoms within Cfps and pinpoint the part of the molecule that needed to be modified to increase the fluorescence yield", says David von Stetten from the Esrf.
In parallel to this work, the Amsterdam team led by Theodorus Gadella used an innovative screening technique to study hundreds of modified Cfp molecules, measuring their fluorescence lifetimes under the microscope to identify which had improved properties. "With the new protein, many studies can now be performed with levels of accuracy and detail that were impossible yesterday. Moreover, thanks to this novel approach taking into account the structural dynamics of the protein, scientists now hope to design improved fluorescent proteins emitting light of different colours for use in other applications", concludes Antoine Royant.

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Fonte: Claus Habfast, European Synchrotron Radiation Facility (Esrf), tel. +33 666 662 384, email claus.habfast@esrf.fr