Keratin fibers visualized using rsEGFP. Scale bar, 10 micrometers.Grotjohann et al., eLifeThe device: Tweaking just a few protein residues, researchers at the Max Planck Institute for Biophysical Chemistry in Germany have created a new type of enhanced GFP (EGFP) protein that enables extremely high resolution of dynamic structures in living cells—without damaging levels of laser power.
The new fluorescent probe, rsEGFP2, is based on an older version of EGFP able to switch reversibly between fluorescent and dark states, rsEGFP. The researchers, led by senior authors Stefan Hell and Stefan Jakobs at Max Planck, mutated only a few amino acids to produce an EGFP that switches more quickly than previous iterations. In a study published last December in eLife, they showed that the new fluorophore also lasts longer, resisting “photofatigue” that wears out fluorescent proteins and leaves them stuck in one state after too many rounds of excitation.
Dynamic imaging of live cells is extremely important to understand their processes, explained Joerg Bewersdorf, a biophysicist at Yale University who was not involved in the research. But many small structures, like organelles, are ...
