N.C. Shaner, et al. "Improved monomeric red, orange and yellow fluorescent proteins derived from Discosoma sp. red fluorescent protein," Nat Biotechnol, 22:1567-72, 2004. (cited in 103 papers) | [PubMed]
Roger Tsien's group at the University of California San Diego has a knack for tinkering with fluorescent proteins. In 2004, they published a follow-up to a 2002 paper reporting the first monomeric red fluorescent protein, mRFP1, this time using molecular evolution to improve the protein's properties and create new red, orange, and yellow color varieties.
Improving qualities such as maturation rate, brightness, and tolerance to terminal fusions required careful balance. Attempts to brighten the new orange monomer, for example, reduced its pH-stability.
The team found that its mOrange protein had a different chromophore structure from that of the green or red varieties....