View source for 8ty1


==Cryo-EM structure of coagulation factor VIII bound to NB2E9==
<StructureSection load='8ty1' size='340' side='right'caption='[[8ty1]], [[Resolution|resolution]] 3.46&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8ty1]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8TY1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8TY1 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.46&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BMA:BETA-D-MANNOSE'>BMA</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8ty1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8ty1 OCA], [https://pdbe.org/8ty1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8ty1 RCSB], [https://www.ebi.ac.uk/pdbsum/8ty1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8ty1 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/FA8_HUMAN FA8_HUMAN] Defects in F8 are the cause of hemophilia A (HEMA) [MIM:[https://omim.org/entry/306700 306700]. A disorder of blood coagulation characterized by a permanent tendency to hemorrhage. About 50% of patients have severe hemophilia resulting in frequent spontaneous bleeding into joints, muscles and internal organs. Less severe forms are characterized by bleeding after trauma or surgery. Note=Of particular interest for the understanding of the function of F8 is the category of CRM (cross-reacting material) positive patients (approximately 5%) that have considerable amount of F8 in their plasma (at least 30% of normal), but the protein is non-functional; i.e. the F8 activity is much less than the plasma protein level. CRM-reduced is another category of patients in which the F8C antigen and activity are reduced to approximately the same level. Most mutations are CRM negative, and probably affect the folding and stability of the protein.<ref>PMID:3012775</ref> <ref>PMID:3122181</ref> <ref>PMID:2833855</ref> <ref>PMID:2835904</ref> <ref>PMID:2499363</ref> <ref>PMID:2506948</ref> <ref>PMID:2510835</ref> <ref>PMID:2495245</ref> <ref>PMID:2498882</ref> <ref>PMID:2104766</ref> <ref>PMID:2105106</ref> <ref>PMID:1973901</ref> <ref>PMID:2105906</ref> <ref>PMID:2106480</ref> <ref>PMID:2107542</ref> <ref>PMID:1908817</ref> <ref>PMID:1908096</ref> <ref>PMID:1851341</ref> <ref>PMID:1356412</ref> <ref>PMID:1639429</ref> <ref>PMID:1349567</ref> <ref>PMID:1301194</ref> <ref>PMID:1301932</ref> <ref>PMID:1301960</ref> <ref>PMID:8449505</ref> <ref>PMID:8322269</ref> <ref>PMID:7579394</ref> <ref>PMID:7794769</ref> <ref>PMID:7759074</ref> <ref>PMID:8644728</ref> <ref>PMID:8639447</ref> <ref>PMID:8759905</ref> <ref>PMID:9029040</ref> <ref>PMID:9326186</ref> <ref>PMID:9341862</ref> <ref>PMID:9886318</ref> <ref>PMID:9450898</ref> <ref>PMID:10215414</ref> <ref>PMID:9603440</ref> <ref>PMID:9452104</ref> <ref>PMID:9792405</ref> <ref>PMID:9829908</ref> <ref>PMID:9569180</ref> <ref>PMID:9569189</ref> <ref>PMID:10554831</ref> <ref>PMID:10338101</ref> <ref>PMID:10408784</ref> <ref>PMID:10404764</ref> <ref>PMID:10910910</ref> <ref>PMID:10910913</ref> <ref>PMID:10691849</ref> <ref>PMID:10886198</ref> <ref>PMID:10800171</ref> <ref>PMID:10896236</ref> <ref>PMID:10612839</ref> <ref>PMID:11410838</ref> <ref>PMID:11298607</ref> <ref>PMID:11442643</ref> <ref>PMID:11442647</ref> <ref>PMID:11554935</ref> <ref>PMID:11748850</ref> <ref>PMID:11341489</ref> <ref>PMID:12351418</ref> <ref>PMID:12406074</ref> <ref>PMID:12199686</ref> <ref>PMID:11857744</ref> <ref>PMID:12203998</ref> <ref>PMID:12325022</ref> <ref>PMID:11858487</ref> <ref>PMID:12195713</ref> <ref>PMID:12930394</ref> <ref>PMID:12871415</ref> <ref>PMID:12614369</ref> <ref>PMID:15682412</ref> <ref>PMID:15810915</ref> <ref>PMID:16805874</ref> <ref>PMID:18184865</ref> <ref>PMID:21371196</ref> 
== Function ==
[https://www.uniprot.org/uniprot/FA8_HUMAN FA8_HUMAN] Factor VIII, along with calcium and phospholipid, acts as a cofactor for factor IXa when it converts factor X to the activated form, factor Xa.[https://www.uniprot.org/uniprot/FA8_PIG FA8_PIG] Factor VIII, along with calcium and phospholipid, acts as a cofactor for factor IXa when it converts factor X to the activated form, factor Xa.
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== Publication Abstract from PubMed ==
BACKGROUND: Hemophilia A arises from dysfunctional or deficient coagulation factor (F)VIII and leads to inefficient fibrin clot formation and uncontrolled bleeding events. The development of antibody inhibitors is a clinical complication in hemophilia A patients receiving FVIII replacement therapy. LE2E9 is an anti-C1 domain inhibitor previously isolated from a mild/moderate hemophilia A patient and disrupts FVIII interactions with von Willebrand factor and FIXa, though the intermolecular contacts that underpin LE2E9-mediated FVIII neutralization are undefined. OBJECTIVES: To determine the structure of the complex between FVIII and LE2E9 and characterize its mechanism of inhibition. METHODS: FVIII was bound to the antigen binding fragment (Fab) of NB2E9, a recombinant construct of LE2E9, and its structure was determined by cryogenic electron microscopy. RESULTS: This report communicates the 3.46 A structure of FVIII bound to NB2E9, with its epitope comprising FVIII residues S2040 to Y2043, K2065 to W2070, and R2150 to H2155. Structural analysis reveals that the LE2E9 epitope overlaps with portions of the epitope for 2A9, a murine-derived inhibitor, suggesting that these residues represent a shared antigenic region on the C1 domain between FVIII(-/-) mice and hemophilia A patients. Furthermore, the FVIII:NB2E9 structure elucidates the orientation of the LE2E9 glycan, illustrating how the glycan sterically blocks interactions between the FVIII C1 domain and the von Willebrand factor D' domain. A putative model of the FVIIIa:FIXa complex suggests potential clashing between the NB2E9 glycan and FIXa light chain. CONCLUSION: These results describe an antigenic "hotspot" on the FVIII C1 domain and provide a structural basis for engineering FVIII replacement therapeutics with reduced antigenicity.

,  PMID:38849084<ref>PMID:38849084</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Sus scrofa]]
[[Category: Childers KC]]
[[Category: Spiegel PC]]