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Isolation and characterization of three Ca2+-dependent beta-galactoside-specific lectins from snake venoms.

ABSTRACT: Three lactose-inhibited lectins from the venoms of the snakes Agkistrodon contortrix contortrix (southern copperhead), Ancistrodon piscivorous leukostoma (western cottonmouth moccasin) and Crotalus atrox (western diamondback rattlesnake) have been isolated and newly characterized. The three lectins are similar to thrombolectin, a lectin isolated from the venom of Bothrops atrox (fer-de-lance) (Gartner, Stocker & Williams, 1980), with regard to sugar specificity, Mr, Ca2+ requirements and sensitivity to reducing agents. Each lectin is a dimer (Mr 28 000) consisting of monomers (Mr 14 000) indistinguishable on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Haemagglutination activity is dependent on the presence of Ca2+ and is inhibited by reducing agents. The lectins are not identical and can be distinguished on the basis of relative affinities for inhibiting sugars, isoelectric points and immunoprecipitation assays using anti-(cottonmouth lectin) serum.

SUBMITTER: Gartner TK

PROVIDER: S-EPMC1144427 | biostudies-other | 1984 Nov

REPOSITORIES: biostudies-other

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Project description:Snake venom proteomes/peptidomes are highly complex and maintenance of their integrity within the gland lumen is crucial for the expression of toxin activities. There has been considerable progress in the field of venom proteomics, however, peptidomics does not progress as fast, because of the lack of comprehensive venom sequence databases for analysis of MS data. Therefore, in many cases venom peptides have to be sequenced manually by MS/MS analysis or Edman degradation. This is critical for rare snake species, as is the case of Bothrops cotiara (BC) and B. fonsecai (BF), which are regarded as near threatened with extinction. In this study we conducted a comprehensive analysis of the venom peptidomes of BC, BF, and B. jararaca (BJ) using a combination of solid-phase extraction and reversed-phase HPLC to fractionate the peptides, followed by nano-liquid chromatography-tandem MS (LC-MS/MS) or direct infusion electrospray ionization-(ESI)-MS/MS or MALDI-MS/MS analyses. We detected marked differences in the venom peptidomes and identified peptides ranging from 7 to 39 residues in length by de novo sequencing. Forty-four unique sequences were manually identified, out of which 30 are new peptides, including 17 bradykinin-potentiating peptides, three poly-histidine-poly-glycine peptides and interestingly, 10 L-amino acid oxidase fragments. Some of the new bradykinin-potentiating peptides display significant bradykinin potentiating activity. Automated database search revealed fragments from several toxins in the peptidomes, mainly from l-amino acid oxidase, and allowed the determination of the peptide bond specificity of proteinases and amino acid occurrences for the P4-P4' sites. We also demonstrate that the venom lyophilization/resolubilization process greatly increases the complexity of the peptidome because of the imbalance caused to the venom proteome and the consequent activity of proteinases on venom components. The use of proteinase inhibitors clearly showed different outcomes in the peptidome characterization and suggested that degradomic-peptidomic analysis of snake venoms is highly sensitive to the conditions of sampling procedures.

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Isolation and characterization of three Ca2+-dependent beta-galactoside-specific lectins from snake venoms.

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