RESUMO
Marine polychaetes Odontosyllis undecimdonta, commonly known as fireworms, emit bright blue-green bioluminescence. Until the recent identification of the Odontosyllis luciferase enzyme, little progress had been made toward characterizing the key components of this bioluminescence system. Here we present the biomolecular mechanisms of enzymatic (leading to light emission) and nonenzymatic (dark) oxidation pathways of newly described O. undecimdonta luciferin. Spectral studies, including 1D and 2D NMR spectroscopy, mass spectrometry, and X-ray diffraction, of isolated substances allowed us to characterize the luciferin as an unusual tricyclic sulfur-containing heterocycle. Odontosyllis luciferin does not share structural similarity with any other known luciferins. The structures of the Odontosyllis bioluminescent system's low molecular weight components have enabled us to propose chemical transformation pathways for the enzymatic and nonspecific oxidation of luciferin.
Assuntos
Substâncias Luminescentes/química , Poliquetos/química , Animais , Vias Biossintéticas , Cor , Indóis/química , Indóis/metabolismo , Substâncias Luminescentes/metabolismo , Medições Luminescentes , Proteínas Luminescentes/metabolismo , Estrutura Molecular , Oxirredução , Poliquetos/metabolismo , Pirazinas/química , Pirazinas/metabolismoRESUMO
Odontosyllis undecimdonta is a marine syllid polychaete that produces bright internal and exuded bioluminescence. Despite over fifty years of biochemical investigation into Odontosyllis bioluminescence, the light-emitting small molecule substrate and catalyzing luciferase protein have remained a mystery. Here we describe the discovery of a bioluminescent protein fraction from O. undecimdonta, the identification of the luciferase using peptide and RNA sequencing, and the in vitro reconstruction of the bioluminescence reaction using highly purified O. undecimdonta luciferin and recombinant luciferase. Lastly, we found no identifiably homologous proteins in publicly available datasets. This suggests that the syllid polychaetes contain an evolutionarily unique luciferase among all characterized luminous taxa.
Assuntos
Luciferases/química , Luciferases/metabolismo , Poliquetos/enzimologia , Sequência de Aminoácidos , Animais , Evolução Molecular , Japão , Luciferases/genética , Luminescência , Poliquetos/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Homologia Estrutural de ProteínaRESUMO
We report the first total synthesis of racemic Odontosyllis undecimdonta luciferin, a thieno[3,2-f]thiochromene tricarboxylate comprising a 6-6-5-fused tricyclic skeleton with three sulfur atoms in different electronic states. The key transformation is based on tandem condensation of bifunctional thiol-phosphonate, obtained from dimethyl acetylene dicarboxylate, with benzothiophene-6,7-quinone. The presented convergent approach provides the synthesis of the target compound with a previously unreported fused heterocyclic core in 11 steps, thus allowing for unambiguous confirmation of the chemical structure of Odontosyllis luciferin by 2D-NMR spectroscopy.