[6] There are currently several different mechanisms describing how the structure of luciferase affects the emission spectrum of the photon and effectively the color of light emitted.

[9] Another mechanism proposes that twisting the angle between benzothiazole and thiazole rings in oxyluciferin determines the color of bioluminescence.

This explanation proposes that a planar form with an angle of 0° between the two rings corresponds to a higher energy state and emits a higher-energy green light, whereas an angle of 90° puts the structure in a lower energy state and emits a lower-energy red light.

Studies suggest that the interactions between the excited state product and nearby residues can force the oxyluciferin into an even higher energy form, which results in the emission of green light.

For example, Arg 218 has electrostatic interactions with other nearby residues, restricting oxyluciferin from tautomerizing to the enol form.

[13] Light is emitted because the CoA synthesis pathway can be converted to the bioluminescence reaction by hydrolyzing the final product via an esterase back to D-luciferin.

[6] Firefly luciferase is thought to be a homolog of long-chain fatty acyl-CoA synthetase because of its ability to synthesize luciferyl-CoA from CoA and dehydroluciferyl-AMP.

Unsurprisingly, Inouye found that the luciferases only showed adenylation activity when exposed to long-chain fatty acids.

The gene product of CG6178 in Drosophila was also found to have high amino acid sequence similarity with firefly luciferase.

[16] According to phylogenetic data, the emergences of these two luciferases appeared even before the families could diverge– indicating their analogous nature due phenotypic convergences.