This domain is the catalytic domain of dinoflagellate luciferase . Luciferase is involved in catalysing the light emitting reaction in bioluminescence. The structure of this domain has been solved [1]. The core part of the domain is a 10 stranded beta barrel that is structurally similar to lipocalins and FABP [1].

1: Crystal structure of a pH-regulated luciferase catalyzing the bioluminescent oxidation of an open tetrapyrrole. Schultz LW, Liu L, Cegielski M, Hastings JW; Proc Natl Acad Sci U S A. 2005;102:1378-1383. PMID:15665092