Luciferase of the Japanese syllid polychaete Odontosyllis umdecimdonta

Highlights: • The polychaete O. undecimdonta uses a luciferin-luciferase bioluminescence system. • O. undecimdonta bioluminescence does not require additional cofactors. • The luciferase of the Japanese fireworm is 329 amino acids long. • Recombinant luciferase is not secreted when expressed in human cells. • Exogenous luciferin does not seem to penetrate cell membranes-only lysate luminesces. 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.