Swammerdam Institute for Life Sciences

SILS researchers set a world record with a new super bright turquoise fluorescent protein

26 March 2012

Using structure-guided molecular evolution, researches in the chair group of Molecular Cytology (dr.ir. J. Goedhart, L. Joosen, dr.ir. M.A. Hink, L. van Weeren & prof. T.W.J. Gadella Jr.) have created a fully genetically encoded turquoise fluorescent protein with the highest efficiency (quantum yield) ever reported for a monomeric fluorescent protein.

Using structure-guided molecular evolution, researches in the chair group of Molecular Cytology (dr.ir. J. Goedhart, L. Joosen, dr.ir. M.A. Hink, L. van Weeren & prof. T.W.J. Gadella Jr.) have created a fully genetically encoded turquoise fluorescent protein with the highest efficiency (quantum yield) ever reported for a monomeric fluorescent protein.

In collaboration with the group of dr. Antoine Royant, scientist at the Synchotron in Grenoble (ESRF, France), the structures of a number of cyan (blue-green) fluorescent proteins are solved (D. von Stetten, M. Noirclerc-Savoye, M. Lelimousin & Antoine Royant).

A thorough analysis revealed a number of amino-acid residues that were suboptimal. The DNA that encodes for these amino acids was subjected to saturated mutagenesis and incorporated into bacteria which produce the corresponding fluorescent proteins. Using a recently developed method for screening fluorescent bacterial colonies, a very bright cyan fluorescent protein was identified, mTurquoise2.

The structure of mTurquoise2 was solved and the spectroscopic properties were examined in vitro and in cells.

Results show that mTurquoise2 has a world-record quantum efficiency of 93% and it is shown that it is the brightest cyan fluorescent protein in living cells. In addition, mTurquoise2 is extremely photostable and can emit 1.6 million fluorescent photons before the chromophore is destroyed.

Due to these properties mTurquoise2 is very suitable for a wide variety of applications in biomedical research, especially those that study disease-related processes in living organisms and cells. Moreover, this variant allows specific applications in which protein-protein interactions are measured quantitatively.

The research has been published in Nature Communications (see: link below).

The DNA encoding mTurquoise2 is freely available for the scientific community and can be requested from the authors.

Two living cancer cells expressing mTurquoise2 fused to a short peptide (LifeAct) which highlights the actin cytoskeleton.

Published by  Swammerdam Institute