2jhm

Structure of globular heads of M-ficolin at neutral pH

spinqualitylabelsall models 2jhm, resolution 1.52Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2jhm is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.52Å Ligands: CA, EPE, IPA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function FCN1_HUMAN Complement-activating lectin and pattern recognition receptor. Binds GlcNAc. Binds preferentially to 9-O-acetylated 2-6-linked sialic acid derivatives and to various glycans containing sialic acid engaged in a 2-3 linkage. 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 Ficolins are soluble oligomeric proteins with lectin-like activity, assembled from collagen fibers prolonged by fibrinogen-like recognition domains. They act as innate immune sensors by recognizing conserved molecular markers exposed on microbial surfaces and thereby triggering effector mechanisms such as enhanced phagocytosis and inflammation. In humans, L- and H-ficolins have been characterized in plasma, whereas a third species, M-ficolin, is secreted by monocytes and macrophages. To decipher the molecular mechanisms underlying their recognition properties, we previously solved the structures of the recognition domains of L- and H-ficolins, in complex with various model ligands (Garlatti, V., Belloy, N., Martin, L., Lacroix, M., Matsushita, M., Endo, Y., Fujita, T., Fontecilla-Camps, J. C., Arlaud, G. J., Thielens, N. M., and Gaboriaud, C. (2007) EMBO J. 24, 623-633). We now report the ligand-bound crystal structures of the recognition domain of M-ficolin, determined at high resolution (1.75-1.8 A), which provides the first structural insights into its binding properties. Interaction with acetylated carbohydrates differs from the one previously described for L-ficolin. This study also reveals the structural determinants for binding to sialylated compounds, a property restricted to human M-ficolin and its mouse counterpart, ficolin B. Finally, comparison between the ligand-bound structures obtained at neutral pH and nonbinding conformations observed at pH 5.6 reveals how the ligand binding site is dislocated at acidic pH. This means that the binding function of M-ficolin is subject to a pH-sensitive conformational switch. Considering that the homologous ficolin B is found in the lysosomes of activated macrophages (Runza, V. L., Hehlgans, T., Echtenacher, B., Zahringer, U., Schwaeble, W. J., and Mannel, D. N. (2006) J. Endotoxin Res. 12, 120-126), we propose that this switch could play a physiological role in such acidic compartments. Structural basis for innate immune sensing by M-ficolin and its control by a pH-dependent conformational switch.,Garlatti V, Martin L, Gout E, Reiser JB, Fujita T, Arlaud GJ, Thielens NM, Gaboriaud C J Biol Chem. 2007 Dec 7;282(49):35814-20. Epub 2007 Sep 26. PMID:17897951 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ficolin

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