White light laser allows orange fluorescent protein to be useful FRET acceptor

Ammasi Periasamy of the University of Virginia as well as colleagues from Florida State and Indiana Universities recently studied the performance of an orange fluorescent protein’s performance as an acceptor in a FRET pairs. Orange fluorescent proteins bridge the gap between green and red/far-red fluorescence proteins but are hard to excite with common fixed wavelength lasers. However, the researchers wanted to see if using a supercontinuum light source--also called a white light laser (WWL)--could help. The researchers studied monomeric Kusabira orange 2 (mKO2) as an FRET acceptor partnered with a monomeric teal (mTFP) donor on a standard FRET construct in live cells. They used a supercontinuum laser with continuous emission from 470 to 670 nm that allowed selection of individual wavelengths in 1-nm increments. The researchers found that that mKO2 and mTFP are good FRET partners with the right imaging setup, specifically exciting the mTFP with an Argon 458 nm laser line and using 540-nm excitation from the supercontinuum laser for mKO2.

See other FRET-related posts here.

Research paper:

http://dx.doi.org/10.1117/1.3227036
Yuansheng Sun, Cynthia F. Booker, Sangeeta Kumari, Richard N. Day, Mike Davidson, Ammasi Periasamy, Characterization of an orange acceptor fluorescent protein for sensitized spectral fluorescence resonance energy transfer microscopy using a white-light laser. J. Biomed. Opt. Vol. 14, 054009.