FIGURE 3.

Structural understanding of DAF-12 species-specific ligand binding. A–C, site-directed mutagenesis validates the structural elements responsible for species-specific ligand binding, as revealed by structural comparison between AceDAF-12 and SstDAF-12 LBDs. Cotransfection assays are performed in COS7 cells. 1 μm (25S)-DA is used. RLU, relative light unit. CelSstDAF12, a hybrid between the N terminus of CelDAF-12 and the LBD of SstDAF-12. We used this chimeric construct because full-length SstDAF-12 expresses poorly in mammalian cells (14).