1nzi
From Proteopedia
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==Overview== | ==Overview== | ||
| - | C1, the complex that triggers the classical pathway of complement, is | + | C1, the complex that triggers the classical pathway of complement, is assembled from two modular proteases C1r and C1s and a recognition protein C1q. The N-terminal CUB1-EGF segments of C1r and C1s are key elements of the C1 architecture, because they mediate both Ca2+-dependent C1r-C1s association and interaction with C1q. The crystal structure of the interaction domain of C1s has been solved and refined to 1.5 A resolution. The structure reveals a head-to-tail homodimer involving interactions between the CUB1 module of one monomer and the epidermal growth factor (EGF) module of its counterpart. A Ca2+ ion is bound to each EGF module and stabilizes both the intra- and inter-monomer interfaces. Unexpectedly, a second Ca2+ ion is bound to the distal end of each CUB1 module, through six ligands contributed by Glu45, Asp53, Asp98, and two water molecules. These acidic residues and Tyr17 are conserved in approximately two-thirds of the CUB repertoire and define a novel, Ca2+-binding CUB module subset. The C1s structure was used to build a model of the C1r-C1s CUB1-EGF heterodimer, which in C1 connects C1r to C1s and mediates interaction with C1q. A structural model of the C1q/C1r/C1s interface is proposed, where the rod-like collagen triple helix of C1q is accommodated into a groove along the transversal axis of the C1r-C1s heterodimer. |
==Disease== | ==Disease== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Arlaud, G | + | [[Category: Arlaud, G J.]] |
| - | [[Category: Fontecilla-Camps, J | + | [[Category: Fontecilla-Camps, J C.]] |
[[Category: Gaboriaud, C.]] | [[Category: Gaboriaud, C.]] | ||
| - | [[Category: Gregory, L | + | [[Category: Gregory, L A.]] |
| - | [[Category: Thielens, N | + | [[Category: Thielens, N M.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: modular structure]] | [[Category: modular structure]] | ||
| - | ''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 14:11:43 2008'' |
Revision as of 12:11, 21 February 2008
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Crystal Structure of the CUB1-EGF Interaction Domain of Complement Protease C1s
Contents |
Overview
C1, the complex that triggers the classical pathway of complement, is assembled from two modular proteases C1r and C1s and a recognition protein C1q. The N-terminal CUB1-EGF segments of C1r and C1s are key elements of the C1 architecture, because they mediate both Ca2+-dependent C1r-C1s association and interaction with C1q. The crystal structure of the interaction domain of C1s has been solved and refined to 1.5 A resolution. The structure reveals a head-to-tail homodimer involving interactions between the CUB1 module of one monomer and the epidermal growth factor (EGF) module of its counterpart. A Ca2+ ion is bound to each EGF module and stabilizes both the intra- and inter-monomer interfaces. Unexpectedly, a second Ca2+ ion is bound to the distal end of each CUB1 module, through six ligands contributed by Glu45, Asp53, Asp98, and two water molecules. These acidic residues and Tyr17 are conserved in approximately two-thirds of the CUB repertoire and define a novel, Ca2+-binding CUB module subset. The C1s structure was used to build a model of the C1r-C1s CUB1-EGF heterodimer, which in C1 connects C1r to C1s and mediates interaction with C1q. A structural model of the C1q/C1r/C1s interface is proposed, where the rod-like collagen triple helix of C1q is accommodated into a groove along the transversal axis of the C1r-C1s heterodimer.
Disease
Known diseases associated with this structure: C1r/C1s deficiency, combined OMIM:[120580], C1s deficiency, isolated OMIM:[120580]
About this Structure
1NZI is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Complement subcomponent C1s, with EC number 3.4.21.42 Full crystallographic information is available from OCA.
Reference
X-ray structure of the Ca2+-binding interaction domain of C1s. Insights into the assembly of the C1 complex of complement., Gregory LA, Thielens NM, Arlaud GJ, Fontecilla-Camps JC, Gaboriaud C, J Biol Chem. 2003 Aug 22;278(34):32157-64. Epub 2003 Jun 4. PMID:12788922
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