Patent ID: 8183036

Claim:
An isolated polynucleotide encoding a modified beetle luciferase comprising an internal insertion of a heterologous amino acid sequence which interacts with a molecule of interest, wherein the activity of the modified beetle luciferase is altered after the molecule of interest interacts with the insertion sequence relative to the activity before the interaction, wherein the modified beetle luciferase is a firefly or click beetle luciferase, wherein if the modified beetle luciferase is a firefly luciferase, the insertion is in a region corresponding to residue 116 to 126, residue 228 to 238, residue 262 to 272, residue 289 to 308, residue 356 to 366, or residue 535 to 546 of SEQ ID NO:103, and wherein if the modified beetle luciferase is a click beetle luciferase, the insertion is in a region corresponding to residue 15 to 30, residue 112 to 122, residue 352 to 362, residue 371 to 384, residue 393 to 414, or residue 485 to 495 of SEQ ID NO:89.