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

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

“…The venom of the scorpion Tityus stigmurus was fractionated into 45 fractions by high-performance liquid chromatography, as previously described [ 26 ]. The fraction containing the toxin Tst3 was eluted at 34.8% acetonitrile ( Figure 1 A) and was subjected to an extra chromatography process with an enhanced gradient to achieve an isolated elution and a high degree of purity for electrophysiological experiments ( Figure 1 B).…”

“…Despite being responsible for a high number of accidents in the Northeast region of Brazil, electrophysiological characterization studies of the venom components of this species are scarce. Among these are studies on toxin Tst1 for voltage-gated sodium channels and on toxins Tst26 and TsTX-Kβ ( Tityus serrulatus toxin with the same sequence as TstβKtx) for voltage-gated potassium channels [ 25 , 26 , 27 , 32 , 33 ].…”

“…The venom of Tityus stigmurus contains several molecular components with high identity to toxins previously identified in the venom of Tityus serrulatus ( Figure 3 ). For example, the toxin Tst1 shares 96.7% identity with Ts1, with both exhibiting β-NaTx activity [ 26 ]. In the present study, we demonstrate the purification, partial sequencing, and electrophysiological characterization of Tst3, as well as a comparative experimental and theoretical analysis of Tst3 and Ts3 modulation on Nav.…”

“…At a concentration of 200 nM, the toxin Tst3 modulated the open probability during activation in all tested channels, inducing a shift in opening towards more hyperpolarized potentials, with values up to 9 mV and an absence of current inhibition ( Table 2 , Figure 5 ). However, this effect is considered weak when compared to the effects of β-NaTxs toxins isolated from scorpion venoms of the genus Tityus (e.g., Ts1, Tst1, and To1), which promote modulations of around 30 mV, associated with current inhibition at concentrations below 100 nM [ 26 , 43 , 44 ]. The observed effect on the open probability of the channel could be understood as a potentially low interaction with the interaction site 4 for neurotoxins.…”

“…Aliquots of 1.0 mg of dried venom were submitted to high-performance liquid chromatography in a reverse-phase configuration (RP-HPLC) (LC10A, Shimadzu, Kyoto, Japan) with a C18 column Synergi Fusion RP 4 mm 80 Å 250 × 4.6 mm (Phenomenex, Torrance, CA, USA). The fractions were separated using a linear gradient of solvent A (0.1% TFA in water) and solvent B (0.1% TFA in acetonitrile) from 0 to 60% for 60 min at flow 1 mL/min flow rate, as previously reported [ 26 ].…”