Figure 7.

Structure-based phylogenetic analysis of the cytokine class I receptor family. Available structures of D1–D3 domains (colored yellow, orange, and salmon pink, respectively) [IL-12RB: 1F45 (PDB ID),⁶³ gp130: 1P9M (PDB ID),⁶⁴ G-CSFR: 2D9Q (PDB ID),⁶⁵ IL-13RA1: 3BPO (PDB ID),⁵⁰ IL-13RA2: 3LB6 (PDB ID)⁵¹] were superposed (for all Cα atoms), and a pairwise distance matrix was constructed based on structural similarity, using the programs ClustalW and DALI. Structure-based sequence identity (%) and Cα atom rmsds (Å), calculated with the program Indonesia (http://xray.bmc.uu.se/dennis), are shown for each domain comparison. Superposition of the α receptors between IL-5RA and IL-13RA1/IL-13/IL-4R (B), and IL-5RA and IL-13RA2/IL-13 (C). All three cytokine-receptor [IL-5RA (D), IL-13RA1 (E), and IL-13RA2 (F)] interactions through the D1 domain share conserved main chain (mc)-main chain (mc) hydrogen bonds (indicated by red dotted lines).