Structural highlights
Function[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. [TAP_ORNMO] TAP is a slow, tight-binding inhibitor of blood coagulation, specific for factor Xa. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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