Chemokine extracellular domain, structure

Fig. 4. Schematic illustration of chemokine-receptor interactions. The transmembrane helices of the receptor, shown as blue tubes, were derived from the structure of rhodopsin (PDB code 1L9H). The chemokine (pink) and the N-terminal extracellular domain of the receptor were derived from the IL8-CXCR1 peptide complex shown in Fig. 5 (PDB code lILP). Except for the N-terminus, the loops of the receptor are not displayed. The figure illustrates the relative size of the receptor and ligand, and the interaction of the receptor N-terminus along one face of the chemokine. The interaction orients the N-terminal signal domain towards the receptor as displayed here it is oriented towards the helical bundle, which may or may not be correct for some chemokines. (See Color Insert.)...

ECL2). Chemokine receptor molecules, therefore, are presumed to adopt compact three-dimensional structures, with all four extracellular domains in close proximity to one another. As a result, it is possible that all four extracellular domains are involved in the conformational interaction with HIV envelope glycoprotein. Moreover, it is likely that a mutation in any one extracellular domain may indirectly affect the function of neighboring regions. 

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