title: BaG, a new dimeric metalloproteinase/disintegrin from the Bothrops alternatus snake venom that interacts with alpha5beta1 integrin.
abstract: The alpha(5)beta(1) integrin is one of the major fibronectin receptors which plays an essential role in the adhesion of normal and tumor cells to extracellular matrix. Here, we describe the isolation and characterization of a novel dimeric metalloproteinase/disintegrin, which is an inhibitor of fibronectin binding to the alpha(5)beta(1) integrin. This protein (BaG) was isolated from the venom of the South American snake Bothrops alternatus by gelatin-Sepharose affinity and anion exchange chromatography. The molecular mass of BaG was approximately 130 kDa under non-reducing conditions and 55 kDa under reducing conditions by SDS-PAGE. BaG shows proteolytic activity on casein that was inhibited by EDTA. 1,10-phenanthroline-treated BaG (BaG-I) inhibits ADP-induced platelet aggregation with an IC(50) of 190 nM. BaG-I inhibits fibronectin-mediated K562 cell adhesion with an IC(50) of 3.75 microM. K562 cells bind to BaG-I probably through interaction with alpha(5)beta(1) integrin, since anti-alpha(5)beta(1) antibodies inhibited K562 cell adhesion to BaG-I. In addition, BaG-I induces the detachment of K562 cells that were bound to fibronectin. In summary, we have purified a novel, dimeric snake venom metalloproteinase/disintegrin that binds to the alpha(5)beta(1) integrin.
authors.affiliation: Departamento de Ciĉncias Fisiológicas, Universidade Federal de São Carlos, Rodovia Washington Luís, Km 235, São Carlos, SP 13565-905, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Cominetti
authors.forename: J U
authors.initials: JU
authors.lastname: Ribeiro
authors.forename: J W
authors.initials: JW
authors.lastname: Fox
authors.forename: H S
authors.initials: HS
authors.lastname: Selistre-de-Araujo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017837:Bothrops / Q000145:classification / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D019281:Dimerization; D019483:Disintegrins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D039081:Integrin alpha5beta1 / Q000378:metabolism; D020014:K562 Cells / Q000187:drug effects / Q000502:physiology; D008666:Metalloendopeptidases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010974:Platelet Aggregation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D012910:Snake Venoms / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D013045:Species Specificity
chemical_list: D019483:Disintegrins; D005353:Fibronectins; D039081:Integrin alpha5beta1; D012910:Snake Venoms; D008666:Metalloendopeptidases