| Red fluorescent protein drFP583 | |
| Organism: | Discosoma sp. |
| Uniprot: | Q9U6Y8 |
Red fluorescent protein (RFP) is a protein which acts as a fluorophore, fluorescing red-orange when excited. The original variant occurs naturally in the coral genus Discosoma, and is named DsRed. Several new variants have been developed using directed mutagenesis[1] which fluoresce orange, red, and far-red.[2]
Like GFP and other fluorescent proteins, RFP is a barrel-shaped protein made primarily out of β-sheet motifs; this type of protein fold is commonly known as a β-barrel.
The mass of RFP is approximately 25.9 kDa. Its excitation maximum is 558 nm, and its emission maximum is 583 nm.[3]
RFP is frequently used in molecular biology research as a fluorescent marker, for a variety of purposes. DsRed has been shown to be more suitable for optical imaging approaches than EGFP.[4]
Issues with fluorescent proteins include the length of time between protein synthesis and expression of fluorescence. DsRed has a maturation time of around 24 hours, which renders it unsuited for experiments that take place over a shorter time frame. Additionally, DsRed exists in a tetrameric form, which can affect the function of proteins to which it is attached. Genetic engineering has improved the utility of RFP by increasing the speed of fluorescence development and creating monomeric variants.[5] Improved variants of RFP include the mFruits variants (mCherry, mOrange, mRaspberry), mKO, TagRFP, mKate, mRuby, FusionRed, mScarlet and DsRed-Express.[6]
The first fluorescent protein to be discovered, green fluorescent protein (GFP), has been adapted to identify and develop fluorescent markers in other colors. Variants such as yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP) were discovered in Anthozoa.