DsRed2 is a tetrameric red fluorescent protein with an excitation peak of 561nm and an emission peak of 587nm in vitro (PMID:11753367). It is an artificial derivative of the naturally occurring fluorescent protein encoded by the Discosoma drFP583 gene (GenBank:AF168419; AAF03369), containing the mutations R2A, K5E, K9T, V105A, I161T and S197A relative to drFP583. The R2A, K5E and K9T mutations prevent the formation of high molecular weight aggregates. In addition, the open-reading frame has been optimized for mammalian codon usage (PMID:11821040).