Solution Structure of LXXLL-related Cofactor Peptide of Orphan Nuclear Receptor FTZ-F1

Abstract

Functional interaction between Drosophila orphan receptor FTZ-F1 (NR5A3) and a segmentation gene product fushi tarazu (FTZ) is crucial for regulating genes related to define the identities of alternate segmental regions in the Drosophila embryo. FTZ binding to the ligand-binding domain (LBD) of FTZ-F1 is of essence in activating its transcription process. We determined solution structures of the cofactor peptide () derived from FTZ by NMR spectroscopy. The cofactor peptide showed a nascent helical conformation in aqueous solution, however, the helicity was increased in the presence of TFE. Furthermore, formed -helical conformation upon FTZ-F1 binding, which provides a receptor bound structure of . The solution structure of in the presence of FTZ-F1 displays a long stretch of the -helix with a bend in the middle of helix.