Hanatoxin 1

Also known as HaTx1; Hanatoxin-1

A tarantula peptide that modifies Kv-channel voltage sensing, widely studied through Kv2.1 gating and membrane interactions.

Length: 35 amino acids
Half-life: Not well characterised
Mechanism: Hanatoxin 1 interacts with the voltage-sensing domain of susceptible voltage-gated potassium channels, particularly Kv2.1, and stabilises resting voltage-sensor conformations. It shifts activation towards more positive potentials rather than acting as a conventional pore plug.
Studied in: Voltage-clamp experiments, channel mutagenesis and membrane-binding assays use hanatoxin 1 to study Kv-channel voltage sensing and toxin–lipid–channel interactions.

About Hanatoxin 1

Hanatoxin 1 is a 35-residue venom peptide originally isolated from a tarantula historically described as Grammostola spatulata. It was characterised alongside a closely related hanatoxin isoform during investigations of potassium-channel inhibition. Three disulphide bonds support an inhibitor cystine-knot scaffold, while an exposed hydrophobic surface contributes to membrane association. Its discovery helped establish that peptide toxins can inhibit voltage-gated channels by altering their gating machinery rather than physically obstructing the ion-conduction pathway.

Kv2.1 is the best-established experimental target, with toxin sensitivity strongly influenced by residues in the extracellular S3–S4 voltage-sensor region. Hanatoxin 1 favours resting sensor states, so sufficiently strong depolarisation can overcome much of the apparent inhibition. This voltage dependence distinguishes its behaviour from simple pore occlusion. Recombinant channels, voltage-sensor substitutions and lipid bilayer experiments are used to examine how membrane partitioning and protein contacts jointly determine the observed gating effect.

Laboratory notes

Document holding potential, conditioning pulses and test-voltage range because voltage-sensor state strongly affects apparent inhibition.
Account for membrane partitioning and equilibration time when comparing recordings across cell systems.
Verify isoform identity and native folding; hanatoxin variants should not be assumed to have identical assay behaviour.

Storage and reconstitution basics: storage guide.

Questions about Hanatoxin 1

Does hanatoxin 1 block the potassium-channel pore?

Its canonical mechanism is voltage-sensor modulation rather than direct pore occlusion, making inhibition dependent on the voltage protocol.

Why is Kv2.1 commonly used in hanatoxin experiments?

Kv2.1 has well-characterised hanatoxin sensitivity and provides a tractable system for mapping toxin contacts and voltage-sensor conformational changes.

Can lipid composition affect the result?

Yes. Membrane association contributes to toxin action, so differences in lipid composition can alter apparent affinity and gating effects.

Is Hanatoxin 1 for human use?

No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.

Related research peptides

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