Molecular model of INSRTR firefly luciferase that maintains its structure with insertion of the unstructured CC-forming peptide (inserted peptide) into the loop. The addition of a regulatory peptide leads to CC formation and thus structural changes in firefly luciferase leading to its inactivation. Both modeled by AlphaFold2; fLuc-firefly luciferase. The values are the means of four biological replicates SD and representative of three independent experiments on plasmid transfected HEK293T cells.