Robust Light Emission from Cyclic Alkylaminoluciferin Substrates for Firefly Luciferase

Firefly luciferase utilizes the chemical energy of ATP and oxygen to convert its substrate, D-luciferin, into an excited-state oxyluciferin molecule. Relaxation of this molecule to the ground state is responsible for the yellow-green light emission. Synthetic cyclic alkylaminoluciferins that allow robust red-shifted light emission with the modified luciferase Ultra-Glo are described. Overall light emission is higher than that of acyclic alkylaminoluciferins, aminoluciferin, and the native substrate D-luciferin.