Firefly oxyluciferin

A very active field of A-2-thiazoline-4-one chemistry concerns 2-(6 -hydroxybenzothiazol-2 -yl)-4-hydroxythiazole (171). which has appeared under the names firefly decarboxy-ketoluciferin " (401, 402) and firefly oxyluciferin (403). This later name is now commonly used (404). 

White, E. H., and Roswell, D. F. (1991). Analogs and derivatives of firefly oxyluciferin, the light emitter in firefly bioluminescence. Photochem. Photobiol. 53 131—136. 

Later, firefly oxyluciferin was successfully synthesized (403. 408) and has been isolated and identified in firefly lanterns (luciola cruaciata) after the lanterns were treated with pyridine and acetic anhydride to prevent decomposition (409). In 1972, Suzuki and Goto firmly established that oxyluciferin is involved in the bioluminescence of firefly lanterns and in the chemiluminescence of firefly luciferin (403. 410). A mechanism involving a four-membered ring cyclic peroxide has been proposed for the reaction (406. 411). However, it was not confirmed by 0ls-labeling experiments (412). 

Fig. 7 Chemical functionalities of the bioluminescence phenomenon (a), neutral and ionic forms of the firefly oxyluciferin molecule (b) and main differences of the chemiluminescence and fluorescence phenomena of a model coelenteramide based on mechanisms and geometrical...

The following schemes represent the overall reaction of firefly bioluminescence (McElroy and DeLuca, 1978), where E is luciferase LH2 is D-luciferin PP is pyrophosphate AMP is adenosine phosphate LH2-AMP is D-luciferyl adenylate (an anhydride formed between the carboxyl group of luciferin and the phosphate group of AMP) and L is oxyluciferin. 

Fig. 1.4 Absorption spectrum of a spent luminescence solution of firefly luciferin containing luciferase-oxyluciferin after dialysis in 0.1 M potassium phosphate, pH 7.8. Replotted from the data of Gates and DeLuca, 1975, with permission from Elsevier.

Fig. 1.5 Fluorescence emission spectrum of the luciferase-oxyluciferin complex in the same solution as in Fig. 1.4 (solid line), compared with the luminescence spectrum of firefly luciferin measured in glycylglycine buffer, pH 7.6 (dotted line). The former curve from Gates and DeLuca, 1975 the latter from Selinger and McElroy, 1960, both with permission from Elsevier.

Fig. 1.12 Mechanism of the bioluminescence reaction of firefly luciferin catalyzed by firefly luciferase. Luciferin is probably in the dianion form when bound to luciferase. Luciferase-bound luciferin is converted into an adenylate in the presence of ATP and Mg2+, splitting off pyrophosphate (PP). The adenylate is oxygenated in the presence of oxygen (air) forming a peroxide intermediate A, which forms a dioxetanone intermediate B by splitting off AMP. The decomposition of intermediate B produces the excited state of oxyluciferin monoanion (Cl) or dianion (C2). When the energy levels of the excited states fall to the ground states, Cl and C2 emit red light (Amax 615 nm) and yellow-green light (Amax 560 nm), respectively.

This finding by Branchini et al. (2002) clearly indicates that 5,5-dimethyloxyluciferin is able to emit the two different colors. This conclusion, however, does not rule out the involvement of the enolized oxyluciferin in the bioluminescence reaction of firefly. 

Orlova et al. (2003) theoretically studied the mechanism of the firefly bioluminescence reaction on the basis of the hybrid density functional theory. According to their conclusion, changes in the color of light emission by rotating the two rings on the 2-2 axis is unlikely, whereas the participation of the enol-forms of oxyluciferin in bioluminescence is plausible but not essential to explain the multicolor emission. They predicted that the color of the bioluminescence depends on the polarization of the oxyluciferin molecule (at its OH and O-termini) in the microenvironment of the luciferase active site the... 

Gates, B. J., and DeLuca, M. (1975). The production of oxyluciferin during the firefly luciferase light reaction. Arch. Biochem. Biophys. 169 616-621. 

C14-0130. A firefly produces light by converting the compound luciferin to oxyluciferin ... 

Figure 3. (a) The firefly luciferase bioluminescence reaction, (b) Structure of the specific substrate luciferin and the corresponding reaction product oxyluciferin. 

Gandelman O.A., Brovko L.Y., Chikishev A.Y., Shkurinov A.P., Ugarova N.N., Investigation of the interaction between firefly luciferase and oxyluciferin or its analogues by steady state and subnanosecond time-resolved fluorescence, J. Photochem. Photobiol. B Biol. 1994 22 203-209. 

Fig. 26 Mechanism of the ATP- and Mg2+-dependent firefly luciferase catalyzed bioluminescence oxidation reaction of D-luciferin (d-LH2) to oxyluciferin (oxy-L)...

A familiar example of chemiluminescence is the light emitted by a firefly. In the firefly reaction, an enzyme, luciferase, catalyzes the oxidative phosphorylation reaction of luciferin with adenosine triphosphate to produce oxyluciferin, carbon dioxide, adenosine monophosphate, and light. Chemiluminescence involving a biological or enzyme reaction is often termed bioluminescence. The popular light stick is another familiar example of chemiluminescence. 

INTERACTION OF OXYLUCIFERIN ANALOGS, DIMETHYL OXYLUCIFERIN AND MONOMETHYL OXYLUCIFERIN, WITH FIREFLY LUCIFERASE... 

Firefly luciferase catalyzes oxidation of luciferin with oxygen in the presence of MgATP. Luciferin (substrate) and oxyluciferin (reaction product) are molecules with pronounced fluorescent properties, therefore, fluorescent methods are widely used to study interactions of luciferase with the substrate, the product, and their analogs. Oxyluciferin is extremely unstable in aqueous solutions, however, one may expect that oxyluciferin analogs, dimethyl oxyluciferin (DMOL) and monomethyl oxyluciferin (MMOL), are more stable. Previously we have studied spectral and fluorescence properties of DMOL in aqueous solutions and it was shown that DMOL at alkaline pH undergoes decomposition to form a product with abs = 350 nm and Xem = 500 nm. The goal of this work was to study absorption and fluorescence spectra of MMOL and stability of MMOL and DMOL in aqueous solutions, and in the complexes with the wild-type and mutant (His433Tyr)... 

Interaction of Oxyluciferin Analogs with Firefly Luciferase... 

Suzuki N, Sato M, Okada K, Goto T. Studies on firefly bioluminescence-II. Identification of oxyluciferin as a product in the bioluminescence of firefly lanterns and in the chemiluminescence of firefly luciferin. Tetrahedron 1972 28 4065-74. 

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