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| Main Authors: | , , , , , , , , , , , |
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| Format: | Artículo científico |
| Language: | en |
| Published: |
The FEBS journal
2025
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| Subjects: | |
| Online Access: | https://pubmed.ncbi.nlm.nih.gov/40251846/ |
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Table of Contents:
- Velamins: green-light-emitting calcium-regulated photoproteins isolated from the ctenophore Velamen parallelum. Soares, Douglas M M Galeazzo, Gabriela A Sgro, Germán G de Moraes, Gabriela V Kronenberg, Leora Borukh, Emmanuella Migotto, Alvaro E Gruber, David F Sparks, John S Pieribone, Vincent A Stevani, Cassius V Oliveira, Anderson G Animals Luminescent Proteins Calcium Ctenophora Cloning, Molecular Light Amino Acid Sequence Pyrazines Imidazoles Ca-regulated photoproteins (CaPhs) consist of single-chain globular proteins to which coelenterazine, a widely distributed marine luminogenic substrate (the luciferin), binds along with molecular oxygen, producing a stable peroxide. Upon Ca addition, CaPhs undergo conformational changes leading to the cyclization of the peroxide and the formation of a high-energy intermediate. Subsequently, its decomposition yields coelenteramide in an excited state and results in the emission of a flash of light. To date, most known CaPh systems emit blue light (λ 465-495 nm), except for two bolinopsin isospecies that emit green light (λ 500 nm). Here, we report the cloning and functional characterization of wild-type CaPhs capable of emitting green light: velamins, isolated from the bioluminescent ctenophore Velamen parallelum. Ten unique photoprotein-like sequences were recovered and grouped in three main clusters. Representative sequences were cloned, expressed, purified, and regenerated into the active His-tagged α-, β-, and γ-velamins. Upon injection of a calcium-containing buffer into the velamin, a flash of green light (λ 500-508 nm) was observed across pH values ranging from 7 to 9. Whilst α-velamin isoforms exhibited the highest light emission activity, β- and γ-velamins were found to be more thermostable at higher temperatures. Velamins are the wild-type CaPhs with the longest-wavelength light emission yet reported, making them an excellent model for investigating spectral modulation mechanisms in photoproteins.