Contryphan-Vn: a modulator of Ca2+-dependent K+ channels

Area of Science:

• Marine Biology and Toxicology
• Neuroscience and Pharmacology

Background:

• Contryphan-Vn is a unique nonapeptide derived from the venom of the Mediterranean cone snail, Conus ventricosus.
• It contains D-tryptophan and a Lys-Trp dyad, a structural motif found in voltage-gated potassium channel blockers.

Purpose of the Study:

• To determine the structure of synthetic Contryphan-Vn using NMR spectroscopy.
• To investigate the effects of Contryphan-Vn on ion channel activity in both invertebrate and vertebrate models.
• To identify the functional targets of Contryphan-Vn within the conopeptide family.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy for structural elucidation.
• Electrophysiological experiments on cockroach dorsal unpaired median neurons.
• Electrophysiological studies on rat fetal chromaffin cells.

Main Results:

• The structure of synthetic Contryphan-Vn was successfully determined.
• Contryphan-Vn demonstrated modulation of both voltage-gated and Ca(2+)-dependent K(+) channel activities.
• Differential effects were observed across invertebrate (cockroach) and vertebrate (rat) systems.

Conclusions:

• Contryphan-Vn represents the first identified functional target for the Contryphan family of conopeptides.
• It is the first conopeptide reported to modulate Ca(2+)-dependent K(+) channels.
• The findings highlight Contryphan-Vn's potential as a pharmacological tool for studying diverse K(+) channel functions.