Opioid Receptor Three-Dimensional Structures from Distance Geometry Calculations with Hydrogen Bonding Constraints  Irina D. Pogozheva, Andrei L. Lomize, Henry I. Mosberg  Biophysical Journal  Volume 75, Issue 2, Pages 612-634 (August 1998) DOI: 10.1016/S0006-3495(98)77552-6 Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 1 Sequence alignment of transmembrane helices (TMH I–TMH VII) and extracellular loops (EL-1, EL-2, EL-3) of human δ, μ, and κ receptors. Asterisks above the sequences for each helix indicate the 26-residue transmembrane segments, identified by Baldwin (1993) and used for identification of GPCR residues as the number of helix (Roman numerals):number of residue in the 26-residue fragment (Arabic numerals). For example, Asp128 in the δ-receptor sequence is denoted as III:7. Numbering of the μ receptor is that of the rat receptor for consistency with mutagenesis data. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 2 Structures of nonpeptide opioid ligands. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 3 Superposition of structures of DIANA-calculated δ (bold line), μ (thin line), and κ (dashed line) receptors (stereo view). The r.m.s.d. between 212Cα atoms of transmembrane helices of δ and μ, δ and κ, and μ and κ receptors are 0.74, 0.80, and 0.90Å, respectively. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 4 Cartoon representation of transmembrane helices and extracellular loops of δ-opioid receptors with JOM-13, side view and top view from the extracellular surface. Helical fragments are purple, loop fragments are white, the β-turn is orange, the disulfide bridge between helix III and EL-2 (residues Cys121–Cys198) is yellow, and JOM-13 is green. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 5 Proposed structure of the β-hairpin in EL-2 of the μ opioid receptor with proximal H-bonded polar residues from helices III and VII and from EL-3 and conserved disulfide bond between Cys140(III:0) and Cys217(EL-2). H-bonds are indicated by the dashed line. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 6 H-bond network of the μ opioid receptor (stereo view). Colors of residues depicted: green, Tyr, Trp; red, Asp, Glu; blue, His, Lys; yellow, Ser, Thr, Asn, Gln. The receptor is shown with morphine (purple) in the binding site. H-bonds are indicated by the dashed line. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 7 Comparison of the δ-opioid receptor model transmembrane α-bundle (blue) and the EM-based model of Baldwin et al. (Baldwin, 1997) (red) (stereo view). Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 8 JOM-13 (bold line) inside the binding pocket of the δ-opioid receptor (stereo view). Conserved (thin solid line) and variable (thin dashed line) residues of the binding pocket (within 4.5Å of the ligand) are also shown. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 9 Superposition of δ and μ receptor models with inserted JOM-13 (dark purple) and JH-42 (dark green), respectively (stereo view). Receptor residues that are within 4.5Å of the ligands and are different in δ and μ receptors are shown in light purple and light green, respectively. Lys214(233) is also shown, because it assumes different side-chain conformers in the δ and μ receptors. Numbering in the figure corresponds to the δ receptor. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 10 Two positions (solid and dashed lines) of (−)-morphine in the binding pocket of the μ-opioid receptor (stereo view). The ligand is denoted by the bold line, and receptor residues within 4.5Å of the ligand by the thin line. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 11 The δ-selective agonist BW373U86 (bold line) inside the binding pocket of the δ-opioid receptor (stereo view). Conserved (thin solid line) and variable (thin dashed line) residues of the binding pocket (within 4.5Å of the ligand) are also shown. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 12 Two conformations of cis-(+)-3-methylfentanyl (B, dashed line; C, solid line) in the μ-opioid receptor (stereo view). The ligand is denoted by the bold line, and receptor residues within 4.5Å of the ligand by the thin line. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 13 The κ-selective alkaloid agonist U69,593 (bold) in the binding pocket of the κ-opioid receptor (stereo view). Conserved (thin solid line) and variable (thin dashed line) residues of the binding pocket within 4.5Å of the ligand are also shown. Biophysical Journal 1998 75, 612-634DOI: (10.1016/S0006-3495(98)77552-6) Copyright © 1998 The Biophysical Society Terms and Conditions