Chemiexcitation Induced Proton Transfer: Enolate Oxyluciferin as the Firefly Bioluminophore

Abstract

Firefly bioluminescence is a phenomenon that attracts attention from the research community because of complex challenges for fundamental investigation, as well as diverse opportunities for practical application. Here we have studied the potential deprotonation of firefly oxyluciferin by using a theoretical approach in an enzymatic-like microenvironment in chemiexcited proton transfer involving adenosine 5'-monophosphate. We have uncovered a reaction route that links the evidence that the light-emitter is an anionic molecule while it is chemiexcited in its neutral form. Moreover, the results indicated that the anionic bioluminophore is the enolate anion and not the ketonic one. Further calculations supported this identification of the light-emitter: the spectrum of resulting enolate anion covers the entire yellow-green/red bioluminescence range, which is in line with the experimental findings regarding firefly multicolor bioluminescence.

Chemiluminescence and Bioluminescence as an Excitation Source in the Photodynamic Therapy of Cancer: A Critical Review

“…The Fluc–luciferin system is characterized by a pH‐sensitive BL, in which the emitted light has a peak wavelength at around 560 nm at basic pH, whereas at acidic pH, the wavelength shifts to a maximum at approximately 620 nm . It should be noted that the identity of the light emitter is still a matter of debate, with some researchers claiming the involvement of an anionic keto species and others favoring the presence of the oxyluciferin enolate …”

Interstate Crossing-Induced Chemiexcitation Mechanism as the Basis for Imidazopyrazinone Bioluminescence

“…While bioluminescence can be found in a variety of organisms (bacteria, dinoflagellates, fungi, crustaceans, worms, insects and fishes), the better characterized system is that of the North‐American firefly Photinus pyralis . Firefly luciferase catalyzes a two‐step reaction, in which luciferin reacts with adenosine‐5’‐triphosphate‐Mg 2+ (ATP‐Mg 2+ ) to generate an adenylyl intermediate . In the second step, this latter compound is oxidized by molecular oxygen, which generates the light‐emitter (firefly oxyluciferin).…”

Effect of very high magnetic field on the optical properties of firefly light emitter oxyluciferin

“…As a result of the efforts devoted, it is nowadays clear, that firefly bioluminescence results from the oxidation process of the substrate molecule luciferin, with the help of the enzyme luciferase [5,7,[20][21][22][23][24][25][26][27][28][29][30]. As illustrated in Fig.…”