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Cloning of cDNAS encoding neurotoxic peptides from the spider Phoneutria nigriventer
E Kalapothakis1, C L Penaforte, P S Beirão
1Departamento de Farmacologia Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Abstract:
A cDNA library made from venom glands of the spider Phoneutria nigriventer was constructed and used to clone neurotoxic peptides. A cDNA of about 360 nucleotides encoding the precursor for the toxin Tx2-1 active on mammals has been isolated. The deduced amino acid sequence for the mature polypeptide confirms the polypeptide sequence previously published. In addition, two new putative toxins called Pn2-1A and Pn2-5A have been characterized and their complete amino acid sequence show 92% similarity to Tx2-1 and 94% similarity to Tx2-5 respectively. The cDNAs revealed that the precursors contain signal peptides characterized by a very hydrophobic core and a propeptide interposed between the signal sequence and the peptide toxin.
Insights
Researchers isolated neurotoxic peptide precursors from the Phoneutria nigriventer spider venom gland cDNA library. This study identified known toxin Tx2-1 and discovered two novel toxins, Pn2-1A and Pn2-5A, with high sequence similarity.
Area of Science:
- * Molecular biology and biochemistry
- * Venom research and neurotoxicology
Background:
- * The venom of the Brazilian wandering spider (Phoneutria nigriventer) contains potent neurotoxins.
- * Understanding these toxins is crucial for developing potential therapeutic agents and studying neuronal function.
Purpose of the Study:
- * To clone and characterize neurotoxic peptides from Phoneutria nigriventer venom glands.
- * To identify novel toxins and elucidate the structure of their precursors.
Main Methods:
- * Construction of a cDNA library from spider venom glands.
- * Isolation and sequencing of complementary DNA (cDNA) encoding neurotoxic peptide precursors.
- * Deduction of amino acid sequences and comparison with known toxins.
Main Results:
- * Isolation of a cDNA encoding the precursor for the known toxin Tx2-1.
- * Characterization of two novel putative toxins, Pn2-1A and Pn2-5A, with high sequence similarity to Tx2-1 and Tx2-5.
- * Identification of signal peptides and propeptides within the toxin precursors.
Conclusions:
- * The study successfully identified and characterized novel neurotoxic peptides from Phoneutria nigriventer.
- * The findings contribute to the understanding of spider venom composition and toxin evolution.
- * These novel toxins may serve as valuable tools in neuroscience research or as leads for drug discovery.