cDNA Cloning and Deduced Amino Acid Sequence of Fibrinolytic Enzyme (Lebetase) fromVipera lebetinaSnake Venom
cDNA Cloning and Deduced Amino Acid Sequence of Fibrinolytic Enzyme (Lebetase) fromVipera lebetinaSnake Venom
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DOI：
10.1006/bbrc.1996.1012
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发表时间：
1996-07
影响因子：
3.1
通讯作者：
E. Siigur;A. Aaspõllu;A. Tu;J. Siigur
中科院分区：
文献类型：
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作者：
E. Siigur;A. Aaspõllu;A. Tu;J. Siigur
摘要 通过筛选中亚Vipera lebetina蛇毒腺c DNA文库，从cDNA克隆的核苷酸序列中推导出lebetase的完整氨基酸序列。具有2011个碱基对的cDNA序列编码478个氨基酸的开放阅读框，其中包括18个氨基酸的信号肽、175个氨基酸的酶原样前肽片段、204个氨基酸的成熟蛋白、18个氨基酸的间隔区和63个氨基酸的解整合素样肽。从粗毒液中分离出的成熟蛋白 lebetase 的分子量约为 23.7 kD，因此 lebetase 以及其他几种蛇毒金属蛋白酶被翻译为前体蛋白，可进行翻译后加工。 lebetase 前蛋白具有“半胱氨酸开关”基序 (PKMCGV)，与参与基质金属蛋白酶酶原激活的基序相似。成熟蛋白（残基223-427）与来自Agkistrodon contortrix contortrix毒液的纤溶酶纤维解酶（63%同一性）显示出最强的相似性。金属蛋白酶结构域具有典型的锌螯合序列 (HEXXHXXGXXH)。在蛋白质的解整合素样结构域中，RGD 序列被 VGD 取代。
Abstract The complete amino acid sequence of lebetase is deduced from the nucleotide sequence of a cDNA clone isolated by screening a venomous gland c DNA library of Central Asian Vipera lebetina snake. The cDNA sequence with 2011 basepairs encodes an open reading frame of 478 amino acids which includes an 18 amino acid signal peptide, plus an 175 amino acid segment of zymogen-like propeptide, a mature protein of 204 amino acids, a spacer of 18 amino acids and a disintegrin-like peptide of 63 amino acids. The mature protein lebetase as isolated from the crude venom has the molecular weight of approximately 23.7 kD and, thus, lebetase as well as several other snake venom metalloproteinases is translated as a precursor protein, which may be processed posttranslationally. The lebetase proprotein has a “cysteine switch” motif (PKMCGV) similar to that involved in the activation of matrix metalloproteinase zymogens. The mature protein (residues 223-427) shows the strongest similarity with fibrolase(63% identity), fibrinolytic enzyme from Agkistrodon contortrix contortrix venom. The metalloproteinase domain has a typical zinc-chelating sequence (HEXXHXXGXXH). In the disintegrin-like domain of protein, the RGD sequence is replaced by VGD.