Extended Data Fig. 7: Comparison of the conformations of the V3 loop and [5P7]CCL5 in complex with CCR5, as well as of gp120-bound CCR5 and G-protein-bound β₂ adrenergic receptor.

a, The structures of the CD4–gp120–CCR5 and [5P7]CCL5–CCR5 complexes are superposed on CCR5 (red). The V3 loop of gp120 with its Pro311 in stick model is in cyan and [5P7]CCL5 with its Pro3 in stick model in yellow. Residues 309–316 of the V3 loop and residues 1–8 of [5P7]CCL5 adopt a very similar structure, and are highlighted in a rectangular box. b, Superposition of the structures of the N terminus of the gp120-bound CCR5 (red) and the complementarity-determining region H3 loop of antibody 412d in complex with gp120 core (green). The electron microscopy density of the CD4–gp120–CCR5 complex is shown in grey. The positions of the sulfated tyrosine (‘Tys’) residues, including Tys10 and Tys14 (from CCR5) and Tys100 and Tys100c (from 412d), are indicated. c, A model for interactions of three CD4 receptors and three CCR5 coreceptors with the SOSIP Env trimer. The side and bottom views of a composite structure of the CD4–CCR5–SOSIP Env trimer complex are shown. The model was generated using the CD4-bound SOSIP trimer (PDB ID: 5VN3) and the structure of the CD4–gp120–CCR5 complex from this study. All the structures were aligned on the basis of the core region of gp120. CCR5 is shown in red, CD4 in green, gp120 in blue, the gp120 of SOSIP in dark blue and the gp41 of SOSIP in grey. The crystallographic dimer of CCR5 (PDB ID: 4MBS) is also shown, on the left only, in a rectangular box. The observed crystallographic dimer of CCR5 or the transmembrane helix 5-mediated dimer by modelling does not seem to be relevant to binding to either monomeric or trimeric gp120^7,78. d, Superposition of the structures of the gp120-bound CCR5 (red) and the G_s-protein-bound β₂ adrenergic receptor (blue). The position of TM6, which is critical for the activation of G-protein-coupled receptors, is indicated.