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Two novel peptides, named Pi4 and Pi7, were purified from the venom of the scorpion Pandinus imperator, and their primary structures were determined. These peptides have 38 amino acids residues, compacted by four disulfide bridges, instead of the normal three found in most K + -channel specific toxins. Both peptides contain 25 identical amino acid residues in equivalent positions (about 66%...
A full-length cDNA sequence encoding the precursor of a venom peptide with homology to chlorotoxin (named BmKCT) was isolated from a cDNA library made from the venom glands of the Chinese Scorpion Buthus martensii Karsch. The encoded precursor of BmKCT was 59 amino acid residues long including a signal peptide of 24 residues and a mature toxin of 35 residues with four disulfide bridges. The sequence...
Three full-length cDNAs, one encoding the precursor of a β-toxin-like peptide (named BmKBT) and the other two encoding those of (MkTx I) homologues (named MkTx II and MkTx III, respectively), were isolated from a venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch, by screening with a cDNA fragment generated by PCR. The encoded precursor of BmKBT contained 83 amino acid residues...
An insect depressant toxin Buthus martensii Karsch insect toxin 4 (BmK IT 4 ) cDNA was cloned into the prokaryotic expression vector pSW202 and expressed in HB101 host cells. The authenticity of this in vitro expressed peptide was confirmed by Western blotting, mass spectrometry and N-terminal peptide sequencing. Bioassays using growth media supplemented with BmK IT 4 demonstrated...
From the venom of the American scorpion Centruroides sculpturatus Ewing we have isolated a minute peptide fraction (named CsEKerg1) which reversibly inhibits the current through ERG (ether-à-go-go-related gene) K+ channels. Isolation was done by CM-cellulose column chromatography and reversed phase high-performance liquid chromatography. To test for an effect on ERG channels we used NG108-15 neuroblastoma×glioma...
We have isolated two cationic peptides, sharing partial homology with each other, from the venom of South African scorpions. Both synthetic peptides-one containing 44 amino acids, the other containing 45 amino acids-were constructed. At submicromolar concentrations they can activate granulocytes as evidenced by a concentration dependent chemotaxis and exocytosis. They also strongly inhibit the production...
Aa1 is a toxin purified from the venom of the North African scorpion Androctonus australis. It blocks fast K + currents in cerebellar granular cells [Biochim. Biophys. Acta 1468 (2000) 203]. Two full-length cDNAs (about 250bp) encoding the precursors of putative Aa1 isoforms (AaTX1 and AaTX2) were amplified by PCR from a venom gland cDNA library of A. australis. The deduced precursors were...
A peptide was isolated from the venom of the scorpion Tityus trivittatus. It is an isoform of the toxin TsTX-IV earlier described [Toxicon 37 (1999) 651] and identical to butantoxin [Arch. Biochem. Biophys. 379 (2000) 18], both isolated from the Brazilian scorpion Tityus serrulatus. This newly characterized peptide contains 40 amino acid residues with a molecular mass of [M+H + ] 4507.0, cross-linked...
Three different immunogens from the venom of the Mexican scorpion Centruroides noxius Hoffmann were used to study protective antibody response in mice and rabbits, challenged with toxin Cn2, one of the most abundant toxic peptide of this venom. The immunogens were: Cn5, a crustacean specific toxin; a recombinant protein containing the peptide Cn5 linked to the maltose transporter and a sub-fraction...
In the present study Tityus fasciolatus crude venom toxicity was evaluated and we also report the purification and characterization of a 6.6 kDa neurotoxin isolated from T. fasciolatus venom. This new toxin, named Tf4, has a molecular mass of 6614Da and its primary structure is homologous to TbIT-I from T. bahiensis and TsTX-VI and TsNTxP from T. serrulatus. Tf4 delays frog sodium channel inactivation...
Two almost identical proteins with 70 amino acid residues each, closely packed by four disufide bridges, and molecular masses of 7899.5 and 7884.7 were isolated and sequenced from the venom of the scorpion Isometrus vittatus from Pakistan. They differ by an acidic amino acid residue (glutamic or aspartic) at the same position 55 of the peptide chain, however, they exhibit the same length, the same...
A new arthropod selective toxin was purified from the venom of the Venezuelan scorpion Tityus discrepans, and its amino acid sequence, cDNA clone and biological activity are reported here. The amino acid sequence of this peptide, named ardiscretin (from arthropod toxin of T. discrepans) was completed by Edman degradation and mass spectrometry. It is a single polypeptide composed by 61 amino acids...
A toxic peptide earlier denominated Tc48b [Toxicon 40 (2002) 557] was purified to homogeneity and its amino acid sequence determined. It has 64 amino acid residues stabilized by four disulfide bridges with a molecular weight of 7,385.2 atomic mass units (a.m.u.). It affects Na + -permeability in pituitary GH3 cells in culture, in a similar fashion as those reported for α-scorpion toxins, contrary...
Much of our knowledge on K + -channels was elucidated using specific peptide ligands isolated from a number of venomous organisms. Recently, this field received a strong support and increased interest due to the solution of the three-dimensional structure of a couple of K + -channels. At the same time, several new subfamilies of specific toxins for K + -channels were isolated...
Scorpion venom is a rich source of bioactive peptides. From the venom of Chinese scorpion Buthus martensi Karsch (BmK), a novel short chain peptide BmKX of 31-amino acid residues was purified, and its amino acid sequence and gene structure were determined. The gene of BmKX was composed of two exons interrupted by an 86-bp intron at the codon-7 upstream of the mature peptide. Although its gene structure...
From the venom of the Mexican scorpion Centruroides elegans Thorell five peptides were isolated to homogeneity by chromatographic procedures and their full amino acid sequence was determined by automatic Edman degradation. They all belong to the Noxiustoxin subfamily of scorpion toxins and were given the systematic names α-KTx 2.8 to 2.12, with trivial names Ce1 to Ce5, respectively. They have 39...
Scorpion venoms contain a large number of bioactive components. Several of the long-chain peptides were shown to be responsible for neurotoxic effects, due to their ability to recognize Na + channels and to cause impairment of channel functions. Here, we revisited the basic paradigms in the study of these peptides in the light of recent data concerning their structure–function relationships,...
Scorpion toxins are important experimental tools for characterization of vast array of ion channels and serve as scaffolds for drug design. General public database entries contain limited annotation whereby rich structure–function information from mutation studies is typically not available. SCORPION2 contains more than 800 records of native and mutant toxin sequences enriched with binding affinity...
The soluble venom from the scorpion Androctonus crassicauda was fractionated by high performance liquid chromatography. At least 44 different sub-fractions were resolved and collected for finger print mass analysis using an electrospray mass spectrometer. This analysis revealed the presence of 80 distinct molecular mass components, from which five were further characterized. A peptide, named Acra1...
Scorpion venom (TX) promotes gastric acid and pepsin secretion leading to acute gastric mucosal lesions (AGML), when injected in animals.The goal of the present study was to observe the effects of acid gastric secretion blockers over the incidence of TX-induced AGML in vivo. To verify this model, we used male albino rats, fasted 18–20h (n=122) and anaesthetized with urethane (1.4g/kg, i.p.). Their...
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