title: Batroxase, a new metalloproteinase from B. atrox snake venom with strong fibrinolytic activity.
abstract: 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 (Pará) 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 C₁₆₄ I₁₆₅M₁₆₆ motif that is associated with a "Met-turn" 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 BmooMPα-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 μg, and was able to hydrolyze extracellular matrix components, such as type IV collagen and fibronectin. The toxin cleaves both α and β-chains of the fibrinogen molecule, and it can be inhibited by EDTA, EGTA and β-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.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, 14040-903 Ribeirão Preto, São Paulo, Brasil.
authors.forename: A C O
authors.initials: AC
authors.lastname: Cintra
authors.forename: L G B
authors.initials: LG
authors.lastname: De Toni
authors.forename: M A
authors.initials: MA
authors.lastname: Sartim
authors.forename: J J
authors.initials: JJ
authors.lastname: Franco
authors.forename: R C
authors.initials: RC
authors.lastname: Caetano
authors.forename: M T
authors.initials: MT
authors.lastname: Murakami
authors.forename: S V
authors.initials: SV
authors.lastname: Sampaio
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017837:Bothrops; D003435:Crotalid Venoms / Q000201:enzymology*; D005342:Fibrinolysis; D007526:Isoelectric Point; D013058:Mass Spectrometry; D045726:Metalloproteases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D003435:Crotalid Venoms; D045726:Metalloproteases