Partial transcriptomic profiling of toxins from the venom gland of the scorpion Parabuthus stridulus

Since it is an apocrine secretion, scorpion venom is a complex mixture that contains a variety of low-molecular-weight basic proteins (neurotoxins), mucus, salts, as well as a large number of other constituents. Diversity of scorpion venom peptides exists also at the transcript level. Two kinds of venom peptides are typically considered: the neurotoxins and the antimicrobial peptides. We constructed a cDNA library and carried an EST (Expressed Sequence Tag) approach to overview the different peptides in the transcriptome of the telson from Parabuthus stridulus. P. stridulus are psammophilous and highly venomous scorpions endemic to Namibia (Prendini 2004) with medical relevance because of important human envenomation occurrence. We obtained 111 ESTs, 20% of them corresponding to cellular process transcripts, 7% to hypothetical proteins and 17% were sequences without good matches, but the majority of ESTs, 56%, corresponds to transcripts encoding for different venom components, including voltage-gated sodium, potassium and calcium channel toxins, antimicrobial peptides and other venom and cell proteins. To the best of our knowledge this report contains the first transcriptome analysis of genes transcribed by the venomous gland of the scorpion species P. stridulus, belonging to the family of medically important Buthidae scorpions. One hundred and eleven ESTs were analyzed, showing an important number of genes that encode for 'products similar to known scorpion venom components. In total, 17 unique and novel sequences were indentified. The identification and characterization of these compounds will be a good source of novel pharmacological tools for studying ion channels and the understanding of the physiological effects of toxins in P. stridulus envenomations at a molecular level. (C) 2014 Elsevier Ltd. All rights reserved

Kbot55, purified from Buthus occitanus tunetanus venom, represents the first member of a novel alpha-KTx subfamily

Invertebrate Neuropeptide Conference 2015 (INC2015)., Bagan, MYANMAR, 2015International audienceKbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65 Da. Kbot55 is very low represented in the venom and thus represents a challenge for biochemical characterization. In this study, Kbot55 has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes. It was found that Kbot55 targets voltage-gated potassium channels with high affinity. Kbot55 shows very low amino acid identity with other scorpion potassium toxins and therefore was considered a bona fide novel type of scorpion toxin. Sequence alignment analysis indicated that Kbot55 is the first representative of the new alpha-Ktx31 subfamily and therefore was classified as alpha-Ktx31.1. (C) 2015 Elsevier Inc. All rights reserved

Kbot55, purified from Buthus occitanus tunetanus venom, represents the first member of a novel α-KTx subfamily

Kbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65Da. Kbot55 is very low represented in the venom and thus represents a challenge for biochemical characterization. In this study, Kbot55 has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes. It was found that Kbot55 targets voltage-gated potassium channels with high affinity. Kbot55 shows very low amino acid identity with other scorpion potassium toxins and therefore was considered a bona fide novel type of scorpion toxin. Sequence alignment analysis indicated that Kbot55 is the first representative of the new α-Ktx31 subfamily and therefore was classified as α-Ktx31.1.publisher: Elsevier articletitle: Kbot55, purified from Buthus occitanus tunetanus venom, represents the first member of a novel α-KTx subfamily journaltitle: Peptides articlelink: http://dx.doi.org/10.1016/j.peptides.2015.05.015 content_type: article copyright: © 2015 Elsevier Inc. All rights reserved.status: publishe