CXCR-1 N-TERMINAL PEPTIDE BOUND TO INTERLEUKIN-8
[IL8_HUMAN] IL-8 is a chemotactic factor that attracts neutrophils, basophils, and T-cells, but not monocytes. It is also involved in neutrophil activation. It is released from several cell types in response to an inflammatory stimulus. IL-8(6-77) has a 5-10-fold higher activity on neutrophil activation, IL-8(5-77) has increased activity on neutrophil activation and IL-8(7-77) has a higher affinity to receptors CXCR1 and CXCR2 as compared to IL-8(1-77), respectively.   [CXCR1_HUMAN] Receptor to interleukin-8, which is a powerful neutrophils chemotactic factor. Binding of IL-8 to the receptor causes activation of neutrophils. This response is mediated via a G-protein that activate a phosphatidylinositol-calcium second messenger system. This receptor binds to IL-8 with a high affinity and to MGSA (GRO) with a low affinity.
Publication Abstract from PubMed
BACKGROUND: Interactions between CXC chemokines (e.g. interleukin-8, IL-8) and their receptors (e.g. CXCR-1) have a key role in host defense and disease by attracting and upregulating neutrophils to sites of inflammation. The transmembrane nature of the receptor impedes structure-based understanding of ligand interactions. Linear peptides based on the N-terminal, extracellular portion of the receptor CXCR-1 do bind to IL-8, however, and inhibit the binding of IL-8 to the full-length receptor. RESULTS: The NMR solution structure of the complex formed between IL-8 and one such receptor-based peptide indicates that a cleft between a loop and a beta hairpin constitute part of the receptor interaction surface on IL-8. Nine residues from the C terminus of the receptor peptide (corresponding to Pro21-Pro29 of CXCR-1) occupy the cleft in an extended fashion. Intermolecular contacts are mostly hydrophobic and sidechain mediated. CONCLUSIONS: The results offer the first details at an atomic level of the interaction between a chemokine and its receptor. Consideration of other biochemical data allow extrapolation to a model for the interaction of IL-8 with the full-length receptor. In this model, the heparin-binding residues of IL-8 are exposed, thereby allowing presentation of the chemokine from endothelial cell-surface glycosaminoglycans. This first glimpse of how IL-8 binds to its receptor provides a foundation for the structure-based design of chemokine antagonists.
Structure of a CXC chemokine-receptor fragment in complex with interleukin-8.,Skelton NJ, Quan C, Reilly D, Lowman H Structure. 1999 Feb 15;7(2):157-68. PMID:10368283
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.