View source for 4bqd


==KD1 of human TFPI in complex with a synthetic peptide==
<StructureSection load='4bqd' size='340' side='right'caption='[[4bqd]], [[Resolution|resolution]] 2.48&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4bqd]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4BQD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4BQD FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.48&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=AIB:ALPHA-AMINOISOBUTYRIC+ACID'>AIB</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=4bqd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4bqd OCA], [https://pdbe.org/4bqd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4bqd RCSB], [https://www.ebi.ac.uk/pdbsum/4bqd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4bqd ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TFPI1_HUMAN TFPI1_HUMAN] Inhibits factor X (X(a)) directly and, in a Xa-dependent way, inhibits VIIa/tissue factor activity, presumably by forming a quaternary Xa/LACI/VIIa/TF complex. It possesses an antithrombotic action and also the ability to associate with lipoproteins in plasma.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Tissue factor pathway inhibitor (TFPI) is a Kunitz-type protease inhibitor that inhibits FXa via a slow-tight binding mechanism and tissue factor-FVIIa (TF-FVIIa) via formation of a quaternary FXa-TFPI-TF-FVIIa complex. Inhibition of TFPI enhances coagulation in hemophilia models. Using a library approach, we selected and subsequently optimized peptides which bind TFPI and block its anticoagulant activity. One peptide (termed compound 3), bound with high affinity to the Kunitz-1 (K1) domain of TFPI (Kd ~1 nM). We solved the crystal structure of this peptide in complex with Kunitz domain 1 of TFPI at 2.55 A resolution. The structure of compound 3 can be segmented into a N-terminal anchor; an Omega-shaped loop; an intermediate segment; a tight glycine-loop; and a C-terminal alpha-helix that is anchored to K1 at its reactive center loop and two-stranded beta-sheet. The contact surface has an overall hydrophobic character with some charged hot spots. In a model system, compound 3 blocked FXa inhibition by TFPI (EC50 = 11 nM) and inhibition of TF-FVIIa-catalysed FX activation by TFPI (EC50 = 2 nM). The peptide prevented the transition from the loose to the tight FXa-TFPI complex, but did not affect formation of the loose FXa-TFPI complex. The K1 domain of TFPI binds and inhibits FVIIa and the K2 domain similarly inhibits FXa. Since compound 3 binds to K1, our data show that K1 is not only important for FVIIa inhibition but also for FXa inhibition i.e. for the transition of the loose to the tight FXa-TFPI complex. This mode of action translates into normalization of coagulation of hemophilia plasmas. Compound 3 thus bears potential to prevent bleeding in hemophilia patients.

Small peptides blocking inhibition of factor Xa and tissue factor-factor VIIa by tissue factor pathway inhibitor (TFPI).,Dockal M, Hartmann R, Fries M, Thomassen MC, Heizmann A, Ehrlich H, Rosing J, Osterkamp F, Polakowski T, Reineke U, Griessner A, Brandstetter H, Scheiflinger F J Biol Chem. 2013 Nov 25. PMID:24275667<ref>PMID:24275667</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4bqd" style="background-color:#fffaf0;"></div>

==See Also==
*[[Tissue factor pathway inhibitor|Tissue factor pathway inhibitor]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Brandstetter H]]
[[Category: Griessner A]]