A biological switch for imaging
CEA
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Life Science Div.
Thursday November 20 2008
CEA
CEA
Researchers at the Jean-Pierre Ebel Institute of Structural Biology (IBS, a CEA-CNRS-Joseph Fourier University of Grenoble joint-run institute) and the ESRF (European Synchrotron Radiation Facility, Grenoble) have joined forces with UK and German teams to successfully engineer a new fluorescent protein derived from GFP (green fluorescent protein). This protein, named Iris-FP, should make it possible to track the spatiotemporal dynamics of proteins using ultra-high-resolution optical microscopy. These findings open up exciting prospects in nanoscopy[1] and biophotonics[2] . The results have just been published in online by the journal Proceedings of the National Academy of Sciences (PNAS).
Over the last couple of years, nanoscopy has emerged into a rapidly-expanding technology in microscopy that allows imaging at spatial resolutions at down to just a few dozen nanometres, thus going far beyond the capabilities of traditional microscopy techniques.
One set of nanoscopy technologies is based on exploiting new fluorescent proteins derived from the natural GFP protein, whose fluorescence can be controllably modulated. The potential rewards of improving on this principle have prompted many structural biology research teams to attempt to engineer new-generation fluorescent proteins. Some of these proteins possess the property of being photoswitchable, i.e. they can be switched 'on' or switched 'off' on demand. Others are capable of photoconversion, which means they can be made to change colour controllably by exciting them with laser light.
The PNAS study reports that the research team developed a new protein, named Iris-FP, that combines both these properties. They employed the X-ray facilities at the ESRF to determine the Iris-FP's atomic structure and characterize each of its light-emitting states.
Iris-FP is a highly versatile highlighter that promises to take the capabilities of microscopy even further. By genetically fusing Iris-FP to a protein of interest, scientists will be able to dynamically track the protein's movements within the cell at unprecedented spatial and temporal resolution.
Besides microscopy, the development of new fluorescent probes raises exciting prospects for nanotechnology. Potentially-pioneering future applications would include the engineering of high-density mass storage media that exploit colour changes in the crystals of these proteins. This would pave the way to storing high volumes of data in a nanometric-sized structure.
[1]Nanoscopy: optical microscopy techniques that make it possible to observe nanoparticles or nano-objects
[2]Biophotonics: the science and technology of using visible, ultra-violet, infrared and even X-ray light emissions to analyze or modulate biological structures
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Référence de l’article :
Virgile Adam, Mickaël Lelimousin, Susan Boehme, Guillaume Desfonds, Karin Nienhaus, Martin J. Field, Joerg Wiedenmann, Sean McSweeney, G. Ulrich Nienhaus, and Dominique Bourgeois. Structural characterization of IrisFP, an optical highlighter undergoing multiple photo-induced transformations.Proceedings of the National Academy of Sciences online the 14th of november 2008.