1kig

<table><tr><td colspan='2'>[[1kig]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Argasid_tick Argasid tick] and [https://en.wikipedia.org/wiki/Bovin Bovin]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KIG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KIG FirstGlance]. <br>

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Coagulation_factor_Xa Coagulation factor Xa], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.6 3.4.21.6] </span></td></tr>

[[https://www.uniprot.org/uniprot/FA10_BOVIN FA10_BOVIN]] Factor Xa is a vitamin K-dependent glycoprotein that converts prothrombin to thrombin in the presence of factor Va, calcium and phospholipid during blood clotting. [[https://www.uniprot.org/uniprot/TAP_ORNMO TAP_ORNMO]] TAP is a slow, tight-binding inhibitor of blood coagulation, specific for factor Xa.

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== Publication Abstract from PubMed ==

The structure of recombinant tick anticoagulant peptide (rTAP) complexed to bovine factor Xa at 3.0 A resolution reveals the structural basis for the specificity and the high affinity of rTAP. Three N-terminal residues, Tyr501, Asn502 and Arg503, play a critical role in the complex formation as suggested by earlier mutagenic studies and the ornithodorin-thrombin complex. Unexpectedly, the side-chain of Tyr501 is located in the S1 pocket, although factor Xa favors arginine as a P1 residue. Arg503 is located at the aryl binding pocket and forms a salt-bridge with Glu97 of factor Xa. The autolysis loop, which is disordered in the uninhibited factor Xa structure, is involved in the formation of the complex as a part of the secondary binding site. The C-terminal helix of rTAP interacts with factor Xa as a secondary binding determinant. The N-terminal residues of rTAP reorganize during the formation of the factor Xa-rTAP complex from the conformation found in the solution into an extended conformation. The presence of the secondary binding site confirms the proposed two-step kinetic mechanism based on the results of a mutagenesis study.

Unexpected binding mode of tick anticoagulant peptide complexed to bovine factor Xa.,Wei A, Alexander RS, Duke J, Ross H, Rosenfeld SA, Chang CH J Mol Biol. 1998;283(1):147-54. PMID:9761680<ref>PMID:9761680</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Argasid tick]]

[[Category: Coagulation factor Xa]]

[[Category: Alexander, R]]

[[Category: Chang, C H]]

[[Category: Wei, A]]

[[Category: Serine protease]]