The periplasmic extract was acquired by using Bacterial Protein Extraction Reagent (B-For every): 4 mL of B-For each and a pair of ul of lysozyme had been included for every gram of cells. Following the cells were lysed completely for 30 min at place temperature, the supernatant was gathered by centrifugation at 15000 × g for 5 min. Nanoluciferase