Selistre de Araujo H S, Ownby C L
Department of Physiological Sciences, Oklahoma State University, Stillwater 74048, USA.
Arch Biochem Biophys. 1995 Jun 20;320(1):141-8. doi: 10.1006/abbi.1995.1352.
The cDNA sequences of two related genes coding for metalloproteinases from a venom gland library of Agkistrodon contortrix laticinctus have been determined. The ACLPREH cDNA codes for a 220-amino acid zinc-dependent hemorrhagic metalloproteinase, and the predicted sequence is in agreement with the N-terminal sequence of the previously purified protein. ACLPREF cDNA sequence predicts a 222-amino acid molecule having strong similarity to fibrolase, a fibrinolytic enzyme isolated from A. contortrix contortrix venom that is reported to be devoid of hemorrhagic activity. Both cDNAs present the same pattern of domain organization as other members of the metalloproteinase/disintegrin gene family. They code for short toxins which do not have the disintegrin domain and have three-disulfide bonds in the metalloproteinase domain. Both cDNA sequences have the highly conserved 5' and 3' untranslated regions that have been described for the metalloproteinase and phospholiphase A2 snake venom gene families. ACLPREH and ACLPREF cDNAs share a higher degree of homology in the untranslated regions and proenzyme domain than in the mature protein domain. The amino acid sequences of hemorrhagic and/or fibrinolytic metalloproteinases demonstrate that a few substitutions may result in different enzymatic activities. Also, some of these toxins have valine instead of isoleucine in the CIM Met-turn consensus sequence. From our data, we can suggest that snake venom fibrinolytic metalloproteinase genes belong to the metalloproteinase/disintegrin gene family. This is the first report of cDNA sequences of small snake venom metalloproteinases having three disulfide bonds in the metalloproteinase domain.
已测定了来自宽带水蛇毒腺文库中两个编码金属蛋白酶的相关基因的cDNA序列。ACLPREH cDNA编码一种含220个氨基酸的锌依赖性出血性金属蛋白酶，预测序列与先前纯化蛋白的N端序列一致。ACLPREF cDNA序列预测出一个含222个氨基酸的分子，与纤维溶酶具有高度相似性，纤维溶酶是一种从扭曲蝮蛇毒中分离出的纤溶酶，据报道无出血活性。两个cDNA呈现出与金属蛋白酶/解整合素基因家族其他成员相同的结构域组织模式。它们编码的短毒素在金属蛋白酶结构域中没有解整合素结构域且有三个二硫键。两个cDNA序列都有金属蛋白酶和磷脂酶A2蛇毒基因家族所描述的高度保守的5'和3'非翻译区。ACLPREH和ACLPREF cDNA在非翻译区和酶原结构域中的同源性高于成熟蛋白结构域。出血性和/或纤溶性金属蛋白酶的氨基酸序列表明，一些替换可能导致不同的酶活性。此外，这些毒素中的一些在CIM Met-turn共有序列中有缬氨酸而非异亮氨酸。根据我们的数据，我们可以认为蛇毒纤溶金属蛋白酶基因属于金属蛋白酶/解整合素基因家族。这是关于在金属蛋白酶结构域中有三个二硫键的小型蛇毒金属蛋白酶cDNA序列的首次报道。
