Ecdysone Receptors: From the Ashburner Model to Structural Biology: Supplemental Video 1

A supplemental video from the 2013 review by Ronald J. Hill, Isabelle M.L. Billas, François Bonneton, Lloyd D. Graham, and Michael C. Lawrence, "Ecdysone Receptors: From the Ashburner Model to Structural Biology," from the Annual Review of Entomology.

This movie depicts schematically the structural transitions within the ligand binding domain of the Heliothis virescens ecdysone receptor EcR from the conformation binding ecdysteroid (PonA, green carbon and red oxygen atoms) to the conformation binding a dibenzoylhydrazine insecticide (BYI06830, black carbon, red oxygen, and blue nitrogen atoms), and then back again. The N and C termini of the receptor domain are denoted by blue and red spheres, respectively. Most features of secondary structure remain effectively unchanged during the transition with the following notable exceptions. The β-sheet (gold) between helices H5 and H6 is disrupted as a concomitant of rotation of two aromatic residues (phenylalanine and tyrosine) to fill the space vacated by the steroid nucleus when the ecdysteroid ligand is replaced by the dibenzoylhydrazine insecticide. Helix H2 (pink) unwinds while helices H7 and H10 (purple) move apart to accommodate the insecticide. To aid interpretation, the two ligands are depicted as transitioning from opaque (present) to fully transparent (absent).