Two novel dermonecrotic toxins LiRecDT4 and LiRecDT5 from brown spider (Loxosceles intermedia) venom: from cloning to functional characterization.
ABSTRACT Loxoscelism (the condition produced by the bite of brown spiders) has been reported worldwide, but especially in warmer regions. Clinical manifestations include skin necrosis with gravitational spreading while systemic loxoscelism may include renal failure, hemolysis and thrombocytopenia. The venom contains several toxins, of which the best biochemically and biologically studied is the dermonecrotic toxin, a phospholipase-D. Purified toxin induces cutaneous and systemic loxoscelism, especially necrotic lesions, hematological disturbances and renal failure. Herein, we describe cloning, heterologous expression and purification of two novel dermonecrotic toxins: LiRecDT4 and LiRecDT5. The recombinant proteins stably expressed in Escherichia coli cells were purified from culture supernatants in a single step using Ni(2+)-chelating chromatography producing soluble proteins of 34 kDa (LiRecDT4) and 37 kDa (LiRecDT5). Circular dichroism analysis evidenced correctly folding for toxins but differences in secondary structures. Both proteins were recognized by whole venom serum antibodies and by a specific antibody to dermonecrotic toxin. Also, recombinant toxins with phospholipase activity induced experimental skin lesions and caused a massive inflammatory response in rabbit skin dermis. Nevertheless, toxins displayed different effects upon platelet aggregation, increase in vascular permeability and not caused death in mice. These characteristics in combination with functional studies illustrates that a family of dermonecrotic toxins exists, and includes two novel members that are useful for future structural and functional studies. They will also be useful in biotechnological ends, for example, as inflammatory and platelet aggregating studies, as antigens for serum therapy source and for lipids biochemical research.
Dataset: Chaim et al, 2011b
Article: Two new phospholipase D isoforms of Loxosceles laeta: cloning, heterologous expression, functional characterization, and potential biotechnological application.[show abstract] [hide abstract]
ABSTRACT: Toxin phospholipases-D present in the venom of Loxosceles spiders is the principal responsible for local and systemic effects observed in the loxoscelism. In this study, we describe the cloning, expression, functional evaluation, and potential biotechnological application of cDNAs, which code for two new phospholipase D isoforms, LIPLD1 and LIPLD2, of the spider Loxosceles laeta. The recombinant protein rLIPLD1 had hydrolytic activity on sphingomyelin and in vitro hemolytic activity on human red blood cells, whereas rLIPLD2 was inactive. The purified recombinant proteins and the venom are recognized by polyclonal anti-rLIPLD1 and rLIPLD2 sera produced in animals and conferred immunoprotection against the venom. These new isoforms reinforce the importance of the multigene family of phospholipases-D present in Loxosceles spiders. A highly immunogenic inactive isoform such as rLIPLD2 raises important expectation for its use as a potential immunogenic inducer of the immunoprotective response to the toxic action of the venom of Loxosceles laeta.Journal of Biochemical and Molecular Toxicology 06/2011; 25(6):393-403. · 1.38 Impact Factor
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ABSTRACT: Venomous animals use their venoms as tools for defense or predation. These venoms are complex mixtures, mainly enriched of proteic toxins or peptides with several, and different, biological activities. In general, spider venom is rich in biologically active molecules that are useful in experimental protocols for pharmacology, biochemistry, cell biology and immunology, as well as putative tools for biotechnology and industries. Spider venoms have recently garnered much attention from several research groups worldwide. Brown spider (Loxosceles genus) venom is enriched in low molecular mass proteins (5-40 kDa). Although their venom is produced in minute volumes (a few microliters), and contain only tens of micrograms of protein, the use of techniques based on molecular biology and proteomic analysis has afforded rational projects in the area and permitted the discovery and identification of a great number of novel toxins. The brown spider phospholipase-D family is undoubtedly the most investigated and characterized, although other important toxins, such as low molecular mass insecticidal peptides, metalloproteases and hyaluronidases have also been identified and featured in literature. The molecular pathways of the action of these toxins have been reported and brought new insights in the field of biotechnology. Herein, we shall see how recent reports describing discoveries in the area of brown spider venom have expanded biotechnological uses of molecules identified in these venoms, with special emphasis on the construction of a cDNA library for venom glands, transcriptome analysis, proteomic projects, recombinant expression of different proteic toxins, and finally structural descriptions based on crystallography of toxins.Toxins. 03/2011; 3(3):309-44.