Patent ID: 7005511

Claim:
An isolated polynucleotide encoding a variant of a red fluorescent protein (RFP) of SEQ ID NO: 1 having a propensity to form tetrameric structures, comprising at least two amino acid alterations with respect to SEQ ID NO: 1, at least one of said at least two amino acid alterations resulting in increased efficiency of maturation compared to the efficiency of maturation of wild-type DsRed of SEQ ID NO:1, and at least one of said at least two amino acid alterations comprising an alteration at the AB interface, at the AC interface, or at the AB and AC interfaces of the wild-type DsRed amino acid sequence of SEQ ID NO: 1, comprising a substitution at an amino acid position selected from the group consisting of 125, 127, 153, 162, 164, 174, 175, 180, 192, 194, 222, 223, 224, and 225 within the wild-type DsRed amino acid sequence of SEQ ID NO: 1 and resulting in a reduced propensity to form tetramers compared to the propensity to form tetramers of wild type DsRed of SEQ ID NO:1.