DHR51, the Drosophila melanogaster homologue of the human photoreceptor cell-specific nuclear receptor, is a thiolate heme-binding protein.
de Rosny E, de Groot A, Jullian-Binard C, Borel F, Suarez C, Le Pape L, Fontecilla-Camps JC, Jouve HM. Biochemistry. 2008 Dec 16; 47(50):13252-60.