Summary
Grafting loops involved in catalysis from one enzyme to another can lead to changes in ligand specificity (1). For example, transferring loops from chymotrypsin to trypsin yielded chymotrypsin-like activity profile, and something similar was observed with luciferase (see Corbella’s citations for this).
1.
Corbella M, Pinto GP, Kamerlin SCL. Loop dynamics and the evolution of enzyme activity. Nature Reviews Chemistry. 2023;7(8):536–47. Available from: https://doi.org/10.1038/s41570-023-00495-w