Tang Yulu, Huang Miao, Hu Qiping, Wu Huayu, Yao Jiali, Sun Kejian, Li Xiaolong
Department of Cell Biology and Genetics, School of Pre-clinical Medicine, Guangxi Medical University, 22 Shuangyong Road, Nanning, 530021, P. R. China.
Department of Radiology, Affiliated Cancer Hospital of Guangxi Medical University, Nanning, 530021, P. R. China.
Chem Biodivers. 2018 Jun;15(6):e1800122. doi: 10.1002/cbdv.201800122. Epub 2018 May 24.
Blood clots produced by snake-venom thrombin-like enzymes (SVTLEs) are cleared rapidly, which makes SVTLEs attractive as potential candidates for antithrombotic therapy. We isolated a SVTLE, agkihpin, from the venom of Gloydius halys Pallas. Agkihpin was confirmed to a single-chain TLE with molecular mass of 25.5 kD, pI of 7.43, optimal pH of 8.0 (hydrolyzing TAME), linked carbohydrate absent, and weak fibrinogen clotting activity. It was also found that (i) G. halys might be the latest species in SVTLEs phylogenetic tree; (ii) different level of conservation was shown among the SVTLEs from the Viperidae snakes. Some of those site may account for different activities exhibited by those SVTLEs, especially position 181, at which a fibrinogenolytic activity increase was found when a basic and larger amino acid substituted by a neutral and smaller one; (iii) an extra α-helix constructed with a 'Pro + acidic amino acid + aromatic amino acid' pattern was found in the SVTLEs from Gloydius and Agkistrodon snakes, although it does not necessarily imply an effect on the fibrinogenolytic activity of the SVTLEs. This study provided some new insight into the activity of SVTLE.
蛇毒类凝血酶（SVTLEs）产生的血凝块能被快速清除，这使得SVTLEs作为抗血栓治疗的潜在候选物具有吸引力。我们从岩栖蝮蛇的毒液中分离出一种SVTLE——agkihpin。agkihpin被确认为一种单链TLE，分子量为25.5 kD，pI为7.43，最佳pH值为8.0（水解TAME），无连接碳水化合物，纤维蛋白原凝血活性较弱。还发现：（i）岩栖蝮蛇可能是SVTLEs系统发育树中的最新物种；（ii）蝰蛇科蛇的SVTLEs之间表现出不同程度的保守性。其中一些位点可能解释了这些SVTLEs表现出的不同活性，尤其是第181位，当一个碱性且较大的氨基酸被一个中性且较小的氨基酸取代时，发现纤维蛋白溶解活性增加；（iii）在岩栖蝮蛇和蝰蛇属蛇的SVTLEs中发现了一个由“脯氨酸+酸性氨基酸+芳香族氨基酸”模式构建的额外α-螺旋，尽管这不一定意味着对SVTLEs的纤维蛋白溶解活性有影响。本研究为SVTLEs的活性提供了一些新的见解。
