3fxi

Crystal structure of the human TLR4-human MD-2-E.coli LPS Ra complex

spinqualitylabelsall models 3fxi, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3fxi is a 4 chain structure with sequence from Homo sapiens. The November 2011 RCSB PDB Molecule of the Month feature on Toll-like Receptors by David Goodsell is 10.2210/rcsb_pdb/mom_2011_11. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.1Å Ligands: DAO, FTT, GCS, GMH, KDO, MG, MYR, NAG, PA1, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease TLR4_HUMAN Genetic variation in TLR4 is associated with age-related macular degeneration type 10 (ARMD10) [MIM:611488. ARMD is a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane. Function TLR4_HUMAN Cooperates with LY96 and CD14 to mediate the innate immune response to bacterial lipopolysaccharide (LPS). Acts via MYD88, TIRAP and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response. Also involved in LPS-independent inflammatory responses triggered by Ni(2+). These responses require non-conserved histidines and are, therefore, species-specific. 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 The lipopolysaccharide (LPS) of Gram negative bacteria is a well-known inducer of the innate immune response. Toll-like receptor (TLR) 4 and myeloid differentiation factor 2 (MD-2) form a heterodimer that recognizes a common 'pattern' in structurally diverse LPS molecules. To understand the ligand specificity and receptor activation mechanism of the TLR4-MD-2-LPS complex we determined its crystal structure. LPS binding induced the formation of an m-shaped receptor multimer composed of two copies of the TLR4-MD-2-LPS complex arranged symmetrically. LPS interacts with a large hydrophobic pocket in MD-2 and directly bridges the two components of the multimer. Five of the six lipid chains of LPS are buried deep inside the pocket and the remaining chain is exposed to the surface of MD-2, forming a hydrophobic interaction with the conserved phenylalanines of TLR4. The F126 loop of MD-2 undergoes localized structural change and supports this core hydrophobic interface by making hydrophilic interactions with TLR4. Comparison with the structures of tetra-acylated antagonists bound to MD-2 indicates that two other lipid chains in LPS displace the phosphorylated glucosamine backbone by approximately 5 A towards the solvent area. This structural shift allows phosphate groups of LPS to contribute to receptor multimerization by forming ionic interactions with a cluster of positively charged residues in TLR4 and MD-2. The TLR4-MD-2-LPS structure illustrates the remarkable versatility of the ligand recognition mechanisms employed by the TLR family, which is essential for defence against diverse microbial infection. The structural basis of lipopolysaccharide recognition by the TLR4-MD-2 complex.,Park BS, Song DH, Kim HM, Choi BS, Lee H, Lee JO Nature. 2009 Apr 30;458(7242):1191-5. Epub 2009 Mar 1. PMID:19252480 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Toll-like Receptor 3D structures

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