Identification of the endogenous cysteine-rich peptide trissin, a ligand for an orphan G protein-coupled receptor in Drosophila

► We identified a ligand of CG34381, trissin in Drosophila. ► Trissin has no significant structural similarities to known endogenous bioactive peptides. ► Trissin is a peptide of 28 amino acids. ► Trissin has three intrachain disulfide bonds.