Patent ID: 7157566

Claim:
An isolated polynucleotide sequence encoding a Discosoma red fluorescent protein (DsRed) variant having a reduced propensity to oligomerize, comprising one or more amino acid substitutions at the AB interface, at the AC interface, or at both the AB and AC interfaces of the wild-type DsRed amino acid sequence of SEQ ID NO: 1, said one or more amino acid substitutions comprising a substitution of an amino acid residue selected from the group consisting of residues 125, 127, 153, 162, 164, 174, 180, 192, 194, 222, 223, 224, and 225, wherein the substitutions result in reduced propensity of the DsRed variant to form tetramers, wherein said variant displays detectable fluorescence of at least one red wavelength.