Unveiling Tst3, a Multi-Target Gating Modifier Scorpion α Toxin from Venom of Northeast Brazil: Evaluation and Comparison with Well-Studied Ts3 Toxin of .

Studies on the interaction sites of peptide toxins and ion channels typically involve site-directed mutations in toxins. However, natural mutant toxins exist among them, offering insights into how the evolutionary process has conserved crucial sequences for activities and molecular target selection. In this study, we present a comparative investigation using electrophysiological approaches and computational analysis between two alpha toxins from evolutionarily close scorpion species of the genus , namely, Tst3 and Ts3 from and , respectively.

The Helix Ring Peptide U from the Venom of the Ant, , Acts as a Putative Pore-Forming Toxin.

An insect neuroactive helix ring peptide called U-MYRTX-Tb1a (abbreviated as U) from the venom of the ant, . U is a 34-amino-acid peptide that is claimed to be one of the most paralytic peptides ever reported from ant venoms acting against blowflies and honeybees. The peptide features a compact triangular ring helix structure stabilized by a single disulfide bond, which is a unique three-dimensional scaffold among animal venoms.

Ts17, a Tityus serrulatus β-toxin structurally related to α-scorpion toxins.

Ts17 was purified from the venom of the scorpion Tityus serrulatus, the most dangerous scorpion species in Brazil. The activity on Na1.1-Na1.

Modulation of hNav by Tst1, a β-toxin purified from the scorpion Tityus stigmurus.

Scorpion venoms are known as a rich mixture of components, including peptides that can interact with different ion channels, particularly voltage-gated potassium channels (Kv), calcium channels (Cav) and sodium channels (Nav), essential membrane proteins for various physiological functions in organisms. The present work aimed to characterize the modulation of hNa-channels by Tst1, a peptide purified from the venom of Tityus stigmurus, using whole-cell patch clamp. Tst1 at 100 nM provoked current inhibition in Nav 1.

Purification and characterization of peptides Ap2, Ap3 and Ap5 (ω-toxins) from the venom of the Brazilian tarantula Acanthoscurria paulensis.

Peptides isolated from spider venoms are of pharmacological interest due to their neurotoxic activity, acting on voltage-dependent ion channels present in different types of human body tissues. Three peptide toxins titled as Ap2, Ap3 and Ap5 were purified by RP-HPLC from Acanthoscurria paulensis venom. They were partially sequenced by MALDI In-source Decay method and their sequences were completed and confirmed by transcriptome analysis of the venom gland.

Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review.

Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity.

Electrophysiological characterization of Tityus obscurus β toxin 1 (To1) on Na-channel isoforms.

To1, previously named Tc49b, is a peptide neurotoxin isolated from venom of the scorpion Tityus obscurus that is responsible for lethal human poisoning cases in the Brazilian Amazonian region. Previously, To1 was shown to be lethal to mice and to change Na permeation in cerebellum granular neurons from rat brain. In addition, To1 did not affect Shaker B K channels.

Subtype Specificity of β-Toxin Tf1a from in Voltage Gated Sodium Channels.

Scorpion venoms are a complex mixture of components. Among them the most important are peptides, which presents the capacity to interact and modulate several ion channel subtypes, including voltage-gated sodium channels (Na). Screening the activity of scorpion toxins on different subtypes of Na reveals the scope of modulatory activity and, in most cases, low channel selectivity.

To4, the first Tityus obscurus β-toxin fully electrophysiologically characterized on human sodium channel isoforms.

Many scorpion toxins that act on sodium channels (NaScTxs) have been characterized till date. These toxins may act modulating the inactivation or the activation of sodium channels and are named α- or β-types, respectively. Some venom toxins from Tityus obscurus (Buthidae), a scorpion widely distributed in the Brazilian Amazon, have been partially characterized in previous studies; however, little information about their electrophysiological role on sodium ion channels has been published.