1apq: Difference between revisions
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
|SITE= <scene name='pdbsite=CAB:prob.+Ca+Binding+Site'>CAB</scene> | |SITE= <scene name='pdbsite=CAB:prob.+Ca+Binding+Site'>CAB</scene> | ||
|LIGAND= | |LIGAND= | ||
|ACTIVITY= [http://en.wikipedia.org/wiki/Complement_subcomponent_C1r Complement subcomponent C1r], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.41 3.4.21.41] | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Complement_subcomponent_C1r Complement subcomponent C1r], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.41 3.4.21.41] </span> | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY= | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1apq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1apq OCA], [http://www.ebi.ac.uk/pdbsum/1apq PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1apq RCSB]</span> | |||
}} | }} | ||
| Line 14: | Line 17: | ||
==Overview== | ==Overview== | ||
The calcium-dependent interaction between C1r and C1s, the two homologous serine proteases of the first component of human complement C1, is mediated by their N-terminal regions. The latter comprise an epidermal growth factor (EGF)-like module exhibiting the consensus sequence characteristic of Ca(2+)-binding EGF modules, surrounded by two CUB modules. Due to its Ca2+ binding ability, the C1r EGF-like module (C1r-EGF) is supposed to participate in the C1r-C1s interaction. An additional interesting feature of C1r-EGF is the unusually large loop connecting the first two conserved cysteine residues. The solution structure of synthetic C1r-EGF (residues 123-175) has been determined using nuclear magnetic resonance and combined simulated annealing-restrained molecular dynamics calculations. The resulting family of 19 structures is characterized by a well-ordered C-terminal part (residues Cys 144-Ala174) with a backbone rmsd of 0.7 A and a disordered N-terminal, including the large loop between the first two cysteines (Cys129 and Cys144). This loop is known to be surface exposed and may be expected to participate in domain-domain or protein-protein interactions. In its C-terminal part, C1r-EGF possesses the characteristic EGF fold with a major and a minor beta-sheet. The latter comprises a beta-bulge, and comparison with other EGF-like modules reveals the existence of two distinct structural and sequential motifs in the bulged part. Additional experiments in the presence of 80 mM Ca2+ did not show significant structural variation of C1r-EGF, in keeping with previous observations on blood-clotting factors IX and X. | The calcium-dependent interaction between C1r and C1s, the two homologous serine proteases of the first component of human complement C1, is mediated by their N-terminal regions. The latter comprise an epidermal growth factor (EGF)-like module exhibiting the consensus sequence characteristic of Ca(2+)-binding EGF modules, surrounded by two CUB modules. Due to its Ca2+ binding ability, the C1r EGF-like module (C1r-EGF) is supposed to participate in the C1r-C1s interaction. An additional interesting feature of C1r-EGF is the unusually large loop connecting the first two conserved cysteine residues. The solution structure of synthetic C1r-EGF (residues 123-175) has been determined using nuclear magnetic resonance and combined simulated annealing-restrained molecular dynamics calculations. The resulting family of 19 structures is characterized by a well-ordered C-terminal part (residues Cys 144-Ala174) with a backbone rmsd of 0.7 A and a disordered N-terminal, including the large loop between the first two cysteines (Cys129 and Cys144). This loop is known to be surface exposed and may be expected to participate in domain-domain or protein-protein interactions. In its C-terminal part, C1r-EGF possesses the characteristic EGF fold with a major and a minor beta-sheet. The latter comprises a beta-bulge, and comparison with other EGF-like modules reveals the existence of two distinct structural and sequential motifs in the bulged part. Additional experiments in the presence of 80 mM Ca2+ did not show significant structural variation of C1r-EGF, in keeping with previous observations on blood-clotting factors IX and X. | ||
==About this Structure== | ==About this Structure== | ||
| Line 35: | Line 35: | ||
[[Category: serine protease]] | [[Category: serine protease]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 18:45:06 2008'' | ||