3f62

Crystal Structure of Human IL-18 in complex with Ectromelia virus IL-18 Binding Protein

spinqualitylabelsall models 3f62, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3f62 is a 2 chain structure with sequence from Ectromelia virus and Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q85319_9POXV Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Human interleukin-18 (hIL-18) is a cytokine that plays an important role in inflammation and host defense against microbes. Its activity is regulated in vivo by a naturally occurring antagonist, the human IL-18-binding protein (IL-18BP). Functional homologs of human IL-18BP are encoded by all orthopoxviruses, including variola virus, the causative agent of smallpox. They contribute to virulence by suppressing IL-18-mediated immune responses. Here, we describe the 2.0-A resolution crystal structure of an orthopoxvirus IL-18BP, ectromelia virus IL-18BP (ectvIL-18BP), in complex with hIL-18. The hIL-18 structure in the complex shows significant conformational change at the binding interface compared with the structure of ligand-free hIL-18, indicating that the binding is mediated by an induced-fit mechanism. EctvIL-18BP adopts a canonical Ig fold and interacts via one edge of its beta-sandwich with 3 cavities on the hIL-18 surface through extensive hydrophobic and hydrogen bonding interactions. Most of the ectvIL-18BP residues that participate in these interactions are conserved in both human and viral homologs, explaining their functional equivalence despite limited sequence homology. EctvIL-18BP blocks a putative receptor-binding site on IL-18, thus preventing IL-18 from engaging its receptor. Our structure provides insights into how IL-18BPs modulate hIL-18 activity. The revealed binding interface provides the basis for rational design of inhibitors against orthopoxvirus IL-18BP (for treating orthopoxvirus infection) or hIL-18 (for treating certain inflammatory and autoimmune diseases). Structural basis for antagonism of human interleukin 18 by poxvirus interleukin 18-binding protein.,Krumm B, Meng X, Li Y, Xiang Y, Deng J Proc Natl Acad Sci U S A. 2008 Dec 30;105(52):20711-5. Epub 2008 Dec 22. PMID:19104048 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Interleukin 3D structures

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