Electrophysiological characterization of the isolated peptide Ts2 from the scorpion Tityus serrulatus on voltage-gated sodium channel Nav 1.7

The project being presented is titled: Electrophysiological characterization of the isolated peptide Ts2 from the scorpion Tityus serrulatus on voltage-gated sodium channel Nav 1.7​. The isolated peptide neurotoxin was obtained through the purification process, by RP-HPLC and had its mass confirmed, by MALDI-TOF with that the Ts2  was submitted to the electrophysiological assay (Patch-clamp) on the sodium channel isoform Nav 1.7, concentration of 100nM. The isolated peptide Ts2 from the Tityus serrulatus, is from the family Buthid, in Brazil this family have the most medical importance due occuring accidents, specially in the Central-West and South-West regions. The peptide toxin has 62 amino acids, one amidations and four disulfide bonds (Uniprot P68410). The presence of disulfide bonds in the chain indicates a high specificity to voltage-gated channels, Ts1(Tityus serrulatus) with 72% identity and Tst2 (Tityus stigmurus) with 100% identity, this specificity is particularly relevant for neuropharmacological studies. The sodium channels can be classified due its activity and physiological action: beta-toxin on opening the channel in more hyperpolarizing direction, and alpha-toxins inhibits/delays the rapid inactivation of the channel. Ts1 and Tst2 are beta-toxins, meanwhile Ts2 is classified as alpha-toxin (Cologna 2012). The methodology of this project consisted on that capture of the scorpion, extraction of its venom, quantification of the venom so it could be separated and purified through RP-HPLC, it was submitted through three steps of purification, and its mass were confirmed though mass spectrometry (MALDI-TOF), after this process the peptide neurotoxin was isolated and it was possible to start the patch-clamp assays, under activation, incantation and recovery protocol. The toxin was eluted on chromatography under 32% of acetonitrile (ACN), on the second and third chromatography under 25% of ACN, the monoisotopic mass [M + H] += 6984,6 Da and for two charge [M+2H]+= 3492,8 Da. Under the electrophysiological assays made on Nav1.7 (100nM) it was possible to observe activity in the activation and inactivation, however under statistical analysis, only the inactivation was seen relevant. Due to the high identity Ts2 has with beta-toxins it is believed it can also have beta activity on sodium channels, however the results do not show this duality.