Ectatotoxin-Rm4a

Overview

Ectatotoxin-Rm4a is a research-grade protein/peptide reagent used in research settings. It is commonly applied as a tool reagent related to Nav1.6, Nav1.7 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: 2994.6 Da, Formula: C148H225N33O33.
• Source / origin: Rhytidoponera metallica (Australian green-headed ant) (Ponera metallica).
• Quality attributes: Purity: ≥98% (HPLC); Bioassay tested: Yes; Sterile / endotoxin-free: No.

Modifications

Asn25 – C-terminal amidation

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

Ectatotoxin-Rm4a (Rm4a), originally isolated from the venom of Rhytidoponera metallica (Australian green-headed ant), is a 26-amino acid cysteine-free peptide toxin that modulates voltage-gated sodium (NaV) channels, particularly NaV1.6 and NaV1.7 subtypes. Rm4a toxin induces sustained sodium currents by delaying inactivation and causing a hyperpolarizing shift in activation voltage. It exhibits higher potency for human Nav1.6 channels (EC50 = 196 ± 23 nM) compared to Nav1.7 (EC50 = 1.9 ± 0.4 µM) and Nav1.8 (EC50 = 8.4 ± 1.0 µM)1. Rm4a toxin, along with other closely related ant venom peptides such as Delta-myrmicitoxin-Ta3a, Myrmicitoxin1-Pm1a, Myrmicitoxin1-Pm2a and Poneratoxin, represents a new class of NaV channel modulators. These toxins are structurally and functionally distinct from previously characterized peptide-based NaV modulators, offering valuable insights into the evolutionary adaptations of ant venom. The effects of these toxins on NaV channel currents more closely resemble those of “site 2” alkaloid toxins, such as batrachotoxin1,2. The toxin's ability to prevent channel inactivation and shift the voltage-dependence of activation can lead to increased neuronal excitability and prolonged action potentials, ultimately resulting in enhanced pain signaling. In mice, Rm4a causes dose-dependent spontaneous nocifensive behaviors, further supporting its potential to induce pain1.

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.