| Field | Specification |
|---|---|
| Mfr No | |
| Accession Number | |
| Activity | |
| Alternative Names | Kappa-theraphotoxin-Gr2c, κ-TRTX-Gr2c, GsAF II, GsAFII, Mechanotoxin-α, KV11.1 channels |
| Concentration | |
| Form | Lyophilized |
| Formulation | |
| Gene ID | |
| Molecular Weight | |
| Product Type | |
| Purity | |
| Reconstitution | |
| Solubility | Centrifuge the vial before adding solvent (10,000 x g for 5 minutes) to spin down all the powder to the bottom of the vial. The lyophilized product may be difficult to visualize. Add solvent directly to the centrifuged vial. Tap the vial to aid in dissolving the lyophilized product. Tilt and gently roll the liquid over the walls of the vial. Avoid vigorous vortexing. Light vortexing for up to 3 seconds is acceptable if needed. The product is soluble in pure water at high micromolar concentrations (100 µM - 1 mM). For long-term storage in solution, we recommend preparing a stock solution by dissolving the product in double-distilled water (ddH2O) at a concentration between 100-1000x of the final working concentration. Divide the stock solution into small aliquots and store at -20°C. Before use, thaw the relevant vial(s) and dilute to the desired working concentration in your working buffer. Centrifuge all product preparations before use. It is recommended to prepare fresh solutions in working buffers just before use. Avoid multiple freeze-thaw cycles to maintain biological activity. |
| Source | Synthetic peptide |
| Species | |
| Storage | |
| Target |
Overview
GsAF-II is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to TTX-sensitive NaV, KV11.1 channels biology and/or assay development. It is supplied in Lyophilized format to support flexible downstream use in RUO workflows. Researchers commonly pair it with applications such as Electrophysiology.
Key elements and design rationale
- Molecular identity: MW: 3979.8 Da, Formula: C176H261N47O45S7.
- Source / origin: Grammostola rosea (Chilean rose tarantula) (Grammostola spatulata).
- Quality attributes: Purity: ≥98% (HPLC); Bioassay tested: Yes; Sterile / endotoxin-free: No.
Modifications
Disulfide bonds between: Cys2-Cys16, Cys9-Cys21 and Cys15-Cys25
When used as a biochemical or pharmacological tool, results are best interpreted relative to the experimental system (species, expression level, and assay readout) and with appropriate negative and competition-style controls where relevant. This product is intended for research use only.
Biological background
The tetrodotoxin (TTX)-sensitive Na+ channels are differentially distributed in the central and peripheral nervous system, in skeletal muscle, and in cardiac muscle1. Several venom-derived peptides are known to modify the gating properties of ion channels, and the study of their mechanisms of action is expected to contribute to the elucidation of the molecular motions associated with channel gating2.Tarantula venoms are a library of interesting compounds, some of which are exquisite modulators of many types of ion channels. A large number of spider toxins have been demonstrated to modulate NaV channels3.GsAF-II (also termed κ-theraphotoxin-Gr2c) is a peptidyl toxin originally isolated from the venom of Grammostola rosea spider. This toxin has antinociceptive and antiarrhythmic effects in mammals. The peptide is reported to block the following voltage-gated Na+ channels: NaV1.1, NaV1.2, NaV1.3, NaV1.4, NaV1.6 and NaV1.7 with IC50 values of 5.7, 12, 24, 4, 6.6 and 1.3 µM, respectively. This peptide also blocks hERG1 with an IC50 value of 4.7 µM4.
Research relevance and current trends
- Using high-specificity ligands, toxins, and engineered peptides to dissect closely related receptor/channel subtypes and signaling microdomains.
- Pairing labeled (e.g., fluorescent) proteins/peptides with advanced imaging to map surface expression, trafficking, and nanoscale organization.
- Increasing emphasis on reproducibility through standardized characterization (identity, purity, and lot QC) and transparent reporting of reagent attributes.
Common research applications
- Electrophysiology: commonly used to compare signal, binding, or functional readouts across conditions without implying a specific protocol.
Across these use cases, changes in signal or functional readout are generally interpreted as evidence of differences in target abundance, accessibility, or engagement, but alternative explanations (matrix effects, off-target interactions, or assay artifacts) should be considered.
Notes for experimental interpretation
- Assay context matters: binding assays, functional modulation, and detection workflows can yield different readouts even for the same target system.
- Target complexity: closely related family members, splice variants, and post-translational modifications can influence apparent specificity and potency.
- Matrix and sample effects: buffer composition, detergents, and biological matrices may alter stability or apparent activity; interpret with appropriate controls.
- Control concepts: include negative controls and orthogonal validation (e.g., genetic perturbation or alternative reagents) to support robust interpretation.
Can’t Find What You’re Looking For? We can help you source the best match or customize a recombinant protein solution for your study. Options may include species (human/mouse/rat), protein region/domain (full-length vs fragment), tag or label (His/GST/FLAG/biotin/fluorescent), expression system (E. coli/HEK293/insect), purity grade, formulation (buffer, carrier-free, glycerol-free), activity/functional validation (binding or enzymatic assays), endotoxin level (low-endotoxin for cell-based work), mutants/variants (point mutations, isoforms), and bulk or custom packaging. Click Talk to a Scientist to submit a request form, email us at support@biohippo.com, or explore our Research Services for additional support. Our team will be in contact with you shortly.
Redaelli, E.
et al. (2010) J. Biol. Chem.285, 4130.
Catterall W.A.
et al. (2005) Pharmacol. Rev. 57, 397.
Escoubas P.
et al. (2004) Toxicon43, 555.
Redaelli, E.
et al. (2010) J. Biol. Chem.285, 4130.
