Batroxase, a new metalloproteinase from B. atrox snake venom with strong fibrinolytic activity

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• 作者：A.C.O. Cintra^a ; L.G.B. De Toni^a ; M.A. Sartim^a ; J.J. Franco^a ; R.C. Caetano^a ; M.T. Murakami^b ; S.V. Sampaio^a ; ^{suvilela@usp.br}
• 关键词：Snake venom metalloproteinase ; Substrate specificity ; Bothrops atrox venom ; Fibrinolytic and thrombolytic activity
• 刊名：Toxicon
• 出版年：2012
• 期刊代码：50_00410101
• 类别：pha
• 出版时间：July, 2012
• 卷：60
• 期：1
• 页码：70-82
• 文件大小：1513 K

摘要

The structures and functional activities of metalloproteinases from snake venoms have been widely studied because of the importance of these molecules in envenomation. Batroxase, which is a metalloproteinase isolated from Bothrops atrox (Par谩) snake venom, was obtained by gel filtration and anion exchange chromatography. The enzyme is a single protein chain composed of 202 amino acid residues with a molecular mass of 22.9 kDa, as determined by mass spectrometry analysis, showing an isoelectric point of 7.5. The primary sequence analysis indicates that the proteinase contains a zinc ligand motif (HELGHNLGISH) and a sequence C₁₆₄I₁₆₅M₁₆₆ motif that is associated with a 鈥淢et-turn鈥?structure. The protein lacks N-glycosylation sites and contains seven half cystine residues, six of which are conserved as pairs to form disulfide bridges. The three-dimensional structure of Batroxase was modeled based on the crystal structure of BmooMP伪-I from Bothrops moojeni. The model revealed that the zinc binding site has a high structural similarity to the binding site of other metalloproteinases. Batroxase presented weak hemorrhagic activity, with a MHD of 10 渭g, and was able to hydrolyze extracellular matrix components, such as type IV collagen and fibronectin. The toxin cleaves both 伪 and 尾-chains of the fibrinogen molecule, and it can be inhibited by EDTA, EGTA and 尾-mercaptoethanol. Batroxase was able to dissolve fibrin clots independently of plasminogen activation. These results demonstrate that Batroxase is a zinc-dependent hemorrhagic metalloproteinase with fibrin(ogen)olytic and thrombolytic activity.