Fig. 4: Chemokine-induced and constitutive activation of CCR5.

a Chemokine-induced conformational change of W248^6.48 and Y251^6.51. The structure of MIP-1α–CCR5–G_i1 is shown in cartoon representation and colored blue (CCR5) and magenta (MIP-1α). The CCR5–maraviroc structure is shown in cartoon representation and colored gray. The ligand maraviroc is shown as yellow sticks. The receptor residues W248^6.48 and Y251^6.51 in the two structures and the MIP-1α residue S1 are shown as sticks. The hydrogen bond between Y251^6.51 and S1 in the MIP-1α–CCR5–G_i1 structure is displayed as a green dashed line. The red arrows indicate the conformational changes of W248^6.48 and Y251^6.51 and the outward movement of helix VI in the MIP-1α–CCR5–G_i1 structure relative to those in the CCR5–maraviroc structure. b Structural comparison of the RANTES–CCR5–G_i1 and CCR5–[5P7]RANTES (PDB ID: 5UIW) complexes. The receptors in the two structures are colored cyan and red, respectively. The chemokines RANTES and [5P7]RANTES are colored orange and purple, respectively. The RANTES residues S1 and S4–T7 and the [5P7]RANTES residues Q0 and L4–L7 are shown as sticks. The hydrogen bond between Y251^6.51 and S1 in the RANTES–CCR5–G_i1 structure is displayed as a green dashed line. The red arrow indicates the movement of the extracellular end of helix VII in the CCR5–[5P7]RANTES structure compared to that in the RANTES–CCR5–G_i1 structure. c Structural comparison of the CCR5–G_i1 (CCR5-apo), MIP-1α–CCR5–G_i1, and CCR5–maraviroc complexes. The receptors in the three structures are colored green, blue, and gray, respectively. MIP-1α is colored magenta. The receptor residues W86^2.60, Y108^3.32, W248^6.48, and Y251^6.51 as well as the MIP-1α residue A3 are shown as sticks. The red arrows indicate the conformational changes of the four receptor residues in the CCR5–G_i1 structure relative to those in the inactive CCR5–maraviroc structure. The residue T82^2.56 in the CCR5–G_i1 structure is also displayed as sticks, showing close proximity to W86^2.60 and Y108^3.32. d Basal activity of the wild-type CCR5 (WT) and mutants of residues involved in constitutive activation. The IP accumulation assay was performed in parallel with the measurement of the IP production using the cells only transfected with the chimeric Gα protein Gα_Δ6qi4myr as a control. The basal activity was calculated by subtracting the IP production measured in the control for the WT receptor and all the mutants and is shown as per cent of the WT activity. The numbers of independent experiments (n) performed in triplicate for the WT and mutants are shown in the parentheses. ***P < 0.0001 by one-way ANOVA followed by Dunnett’s post-test, compared with the basal activity of the WT (WT-maraviroc, W86F, W86A, Y108F, and Y251F: P < 0.0001). See Supplementary Table 1 for detailed statistical evaluation and expression level. Source data are provided as a Source Data file.