Wan Shao-Gui, Jin Yang, Lee Wen-Hui, Zhang Yun
Department of Animal Toxinology, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
Toxicon. 2006 Mar 15;47(4):465-72. doi: 10.1016/j.toxicon.2006.01.003. Epub 2006 Feb 17.
Hemorrhagic toxins are widely distributed in viperid and crotalid snake venoms. Envenomation of Trimeresurus stejnegeri, a member of Crotalidae family, caused potent systemic and local hemorrhage. Up to now, there is no report on hemorrhage toxins from this venom. In this work, we cloned two cDNAs of P-III metalloproteinase precursors, designated as stejnihagin-A and stejnihagin-B, respectively, from T. stejnegeri venom gland. Both cDNAs encode an opening reading frame of 600 amino acid residues, containing a signal sequence, a proprotein domain, a metalloproteinase domain, a disintegrin-like domain and a cystetine-rich domain. Sequence analysis suggested that these two sequences shared highest similarity to the hemorrhagic toxin HR1b from T. flavoviridis. Aligning the deduced mature protein sequences of stejnihagin-A and stejnihagin-B with other snake venom metalloproteinases (SVMPs), we observed that stejnihagin-A and stejnihagin-B, together with HR1b shared the common cysteinyl residue at the position 100 in the metalloproteinase domain. In combination with the phylogenetic analysis, we presumed that stejnihagin-A, stejnihagin-B and HR1b might constitute a novel subclass of P-III SVMPs, named P-IIIc.
出血毒素广泛分布于蝰蛇科和响尾蛇科蛇毒中。竹叶青蛇（蝰蛇科的一员）的毒液注入会导致严重的全身和局部出血。到目前为止，尚无关于这种毒液中出血毒素的报道。在这项研究中，我们从竹叶青蛇毒腺中克隆了两个P-III金属蛋白酶前体的cDNA，分别命名为竹叶青毒素-A和竹叶青毒素-B。这两个cDNA都编码一个由600个氨基酸残基组成的开放阅读框，包含一个信号序列、一个前蛋白结构域、一个金属蛋白酶结构域、一个解整合素样结构域和一个富含半胱氨酸的结构域。序列分析表明，这两个序列与来自日本竹叶青蛇的出血毒素HR1b具有最高的相似性。将竹叶青毒素-A和竹叶青毒素-B推导的成熟蛋白序列与其他蛇毒金属蛋白酶（SVMPs）进行比对，我们观察到竹叶青毒素-A和竹叶青毒素-B与HR1b在金属蛋白酶结构域的第100位共享相同的半胱氨酸残基。结合系统发育分析，我们推测竹叶青毒素-A、竹叶青毒素-B和HR1b可能构成P-III SVMPs的一个新亚类，命名为P-IIIc。
