Patent ID: 8822162

Claim:
An isolated polypeptide comprising a modified blue/green light absorbing Thermosynechococcus elongatus phytochrome domain, wherein the modified phytochrome domain has at least 85% amino acid sequence identity to the amino acid sequence of positions 1 to 162 of SEQ ID NO: 1, wherein the modified phytochrome domain has an amino acid other than Asp at the residue corresponding to position 63 of SEQ ID NO: 1 or an amino acid other than Asp at the residue corresponding to position 63 of SEQ ID NO: 1 in combination with an amino acid other than Cys at the residue corresponding to position 65 of SEQ ID NO: 1, and wherein the modified phytochrome domain has increased fluorescent activity compared with fluorescent activity of a phytochrome domain comprising the amino acid sequence from positions 1 to 162 of SEQ ID NO: 1.