A Synthetic Factor XIIa Inhibitor Blocks Selectively Intrinsic Coagulation Initiation
A Synthetic Factor XIIa Inhibitor Blocks Selectively Intrinsic Coagulation Initiation
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DOI：
10.1021/acschembio.5b00103
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发表时间：
2015-08-01
影响因子：
4
通讯作者：
Heinis, Christian
中科院分区：
文献类型：
--
作者：
Baeriswyl, Vanessa;Calzavarini, Sara;Heinis, Christian
凝血因子XII （FXII）抑制剂对研究内在凝血途径中的蛋白酶、抑制凝血试验中的接触活化具有重要意义，并且在抗血栓治疗中具有潜在的应用前景。然而，迄今为止开发的合成FXII抑制剂具有较弱的结合亲和力和/或较差的选择性。在此，我们开发了一种抑制活化的FXII （FXLIIa）的肽大环，其抑制常数K-i为22 nM，选择性为其他蛋白酶的2000倍。序列和结构分析表明，体外进化的肽的两个大细胞环中有一个模拟了玉米胰蛋白酶抑制剂的结合环，玉米胰蛋白酶抑制剂是一种天然的基于蛋白质的FXIIa抑制剂。合成抑制剂阻断了内在凝血起始，而不影响外在凝血。此外，肽大环有效地抑制了血液与样管接触引发的血浆凝固，并允许对组织因子引发的凝固进行特异性研究。
Coagulation factor XII (FXII) inhibitors are of interest for the study of the protease in the intrinsic coagulation pathway, for the suppression of contact activation in blood coagulation assays, and they have potential application in antithrombotic therapy. However, synthetic FXII inhibitors developed to date have weak binding affinity and/or poor selectivity. Herein, we developed a peptide macrocycle that inhibits activated FXII (FXLIIa) with an inhibitory constant K-i of 22 nM and a selectivity of >2000-fold over other proteases. Sequence and structure analysis revealed that one of the two macrocydic rings of the in vitro evolved peptide mimics the combining loop of corn trypsin inhibitor, a natural protein-based inhibitor of FXIIa. The synthetic inhibitor blocked intrinsic coagulation initiation without affecting extrinsic coagulation. Furthermore, the peptide macrocycle efficiently suppressed plasma coagulation triggered by contact of blood with sample tubes and allowed specific investigation of tissue factor initiated coagulation.