2ok5: Difference between revisions
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New page: left|200px<br /> <applet load="2ok5" size="450" color="white" frame="true" align="right" spinBox="true" caption="2ok5, resolution 2.30Å" /> '''Human Complement fa... |
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[[Image:2ok5. | [[Image:2ok5.jpg|left|200px]]<br /><applet load="2ok5" size="350" color="white" frame="true" align="right" spinBox="true" | ||
<applet load="2ok5" size=" | |||
caption="2ok5, resolution 2.30Å" /> | caption="2ok5, resolution 2.30Å" /> | ||
'''Human Complement factor B'''<br /> | '''Human Complement factor B'''<br /> | ||
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==Overview== | ==Overview== | ||
Factor B is the central protease of the complement system of immune, defense. Here, we present the crystal structure of human factor B at 2.3-A, resolution, which reveals how the five-domain proenzyme is kept securely, inactive. The canonical activation helix of the Von Willebrand factor A, (VWA) domain is displaced by a helix from the preceding domain linker. The, two helices conformationally link the scissile-activation peptide and the, metal ion-dependent adhesion site required for binding of the ligand C3b., The data suggest that C3b binding displaces the three N-terminal control, domains and reshuffles the two central helices. Reshuffling of the helices, releases the scissile bond for final proteolytic activation and generates, a new interface between the VWA domain and the serine protease domain., This allosteric mechanism is crucial for tight regulation of the, complement-amplification step in the immune response. | Factor B is the central protease of the complement system of immune, defense. Here, we present the crystal structure of human factor B at 2.3-A, resolution, which reveals how the five-domain proenzyme is kept securely, inactive. The canonical activation helix of the Von Willebrand factor A, (VWA) domain is displaced by a helix from the preceding domain linker. The, two helices conformationally link the scissile-activation peptide and the, metal ion-dependent adhesion site required for binding of the ligand C3b., The data suggest that C3b binding displaces the three N-terminal control, domains and reshuffles the two central helices. Reshuffling of the helices, releases the scissile bond for final proteolytic activation and generates, a new interface between the VWA domain and the serine protease domain., This allosteric mechanism is crucial for tight regulation of the, complement-amplification step in the immune response. | ||
==About this Structure== | ==About this Structure== | ||
2OK5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with NAG and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alternative-complement-pathway_C3/C5_convertase Alternative-complement-pathway C3/C5 convertase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.47 3.4.21.47] Full crystallographic information is available from [http:// | 2OK5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=NAG:'>NAG</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alternative-complement-pathway_C3/C5_convertase Alternative-complement-pathway C3/C5 convertase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.47 3.4.21.47] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OK5 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: von willebrand factor-a domain]] | [[Category: von willebrand factor-a domain]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 15:04:09 2008'' | ||
