Catalytic mechanism for Renilla-type luciferases
| Authors | |
|---|---|
| Year of publication | 2023 |
| Type | Article in Periodical |
| Magazine / Source | Nature Catalysis |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.nature.com/articles/s41929-022-00895-z |
| Doi | http://dx.doi.org/10.1038/s41929-022-00895-z |
| Keywords | CYPRIDINA LUCIFERIN; PROTEIN CRYSTALLIZATION; BIOLUMINESCENCE; RENIFORMIS; LIGHT; CHEMILUMINESCENCE; COELENTERAZINE; STABILITY; LUMINESCENCE; SPECIFICITY |
| Description | The widely used coelenterazine-powered Renilla luciferase was discovered over 40 years ago, but the oxidative mechanism by which it generates blue photons remains unclear. Here we decipher Renilla-type catalysis through crystallographic, spectroscopic and computational experiments. Structures of ancestral and extant luciferases complexed with the substrate-like analogue azacoelenterazine or a reaction product were obtained, providing molecular snapshots of coelenterazine-to-coelenteramide oxidation. Bound coelenterazine adopts a Y-shaped conformation, enabling the deprotonated imidazopyrazinone component to attack O-2 via a radical charge-transfer mechanism. A high emission intensity is secured by an aspartate from a conserved proton-relay system, which protonates the excited coelenteramide product. Another aspartate on the rim of the catalytic pocket fine-tunes the electronic state of coelenteramide and promotes the formation of the blue light-emitting phenolate anion. The results obtained also reveal structural features distinguishing flash-type from glow-type bioluminescence, providing insights that will guide the engineering of next-generation luciferase-luciferin pairs for ultrasensitive optical bioassays. |
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