2jhh
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Ficolins are soluble oligomeric proteins with lectin-like activity, assembled from collagen fibers prolonged by fibrinogen-like recognition | + | 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. |
==About this Structure== | ==About this Structure== | ||
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==Reference== | ==Reference== | ||
| - | 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 Sep 26 | + | 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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17897951 17897951] |
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Arlaud, G | + | [[Category: Arlaud, G J.]] |
[[Category: Gaboriaud, C.]] | [[Category: Gaboriaud, C.]] | ||
[[Category: Garlatti, V.]] | [[Category: Garlatti, V.]] | ||
[[Category: Gout, E.]] | [[Category: Gout, E.]] | ||
[[Category: Martin, L.]] | [[Category: Martin, L.]] | ||
| - | [[Category: Reiser, J | + | [[Category: Reiser, J B.]] |
| - | [[Category: Thielens, N | + | [[Category: Thielens, N M.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: acidic ph]] | [[Category: acidic ph]] | ||
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[[Category: sugar-binding protein]] | [[Category: sugar-binding protein]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:03:22 2008'' |
Revision as of 16:03, 21 February 2008
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STRUCTURE OF GLOBULAR HEADS OF M-FICOLIN AT ACIDIC PH
Overview
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.
About this Structure
2JHH is a Single protein structure of sequence from Homo sapiens with as ligand. Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Thu Feb 21 18:03:22 2008
Categories: Homo sapiens | Single protein | Arlaud, G J. | Gaboriaud, C. | Garlatti, V. | Gout, E. | Martin, L. | Reiser, J B. | Thielens, N M. | CA | Acidic ph | Collagen | Complement | Glycoprotein | Innate immunity | Lectin | Polymorphism | Sugar-binding protein
