Red Fluorescent Proteins and Their Applications

Bernard Loo, GIT, IBB 3428, 315 Ferst Dr, Atlanta, GA 30332, Karen M. Polizzi, School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Dr, Atlanta, GA 30332, and Andreas S. Bommarius, Georgia Institute of Technology, School of Chemical Engineering, 315 Ferst Drive N.W., Parker H. Petit Biotechnology Institute, Room 3310, Atlanta, GA 30332-0363.

Fluorescent proteins have proven to be a useful tool for bio-imaging, protein interaction, sensing and chemical detection. Red fluorescent proteins have emissions above 580nm which makes them an ideal protein for in vivo bio-imaging. The mRFP protein with emissions at 607nm is one of the few monomeric far red-shifted proteins that are useful for tag-fusion expression purposes. DsRed is an obligate tetramer that has emissions at 590nm while HcRed has emissions reaching 615nm but it is disadvantaged as it is a dimeric protein which negates its use as a tag fusion expression partner. The maturation of the red fluorescent proteins follows a series of oxidative and dehydration steps after folding to form the mature chromophore that consist of a series of conjugated bonds that permit fluorescence. The mRFP was synthesized, mutated and screened for improved functionality. The applications of red fluorescent proteins for resonance energy transfer will be reported.