AG 489

A neurotoxic peptide from spider venom

Overview

AG 489 is a neurotoxic peptide derived from the venom of the funnel-web spider, specifically from the species Agelenopsis aperta. This toxin is part of a larger family of agatoxins, which are known for their ability to affect ion channels in neurons. AG 489 is particularly notable for its action on calcium channels, which play a crucial role in the transmission of nerve impulses.

Structure

Structure of AG 489

AG 489 is a peptide composed of a specific sequence of amino acids that allows it to interact with neuronal ion channels. The structure of AG 489 is characterized by a series of disulfide bonds that stabilize its conformation, which is essential for its biological activity. The precise arrangement of these bonds and the overall three-dimensional shape of the peptide enable it to bind selectively to its target channels.

Mechanism of Action

AG 489 exerts its effects by binding to voltage-gated calcium channels on the surface of neurons. This binding inhibits the normal influx of calcium ions that is necessary for the release of neurotransmitters at the synapse. By blocking these channels, AG 489 effectively disrupts synaptic transmission, leading to paralysis in prey organisms. This mechanism is similar to that of other neurotoxins that target ion channels, such as conotoxins and saxitoxin.

Biological Effects

The primary biological effect of AG 489 is the inhibition of synaptic transmission, which can lead to paralysis and, ultimately, death in affected organisms. This makes AG 489 a potent tool for the spider in capturing prey. In a research context, AG 489 and related agatoxins are valuable for studying the function of calcium channels and the role of calcium in neuronal signaling.

Applications in Research

AG 489 is used in neuroscience research to investigate the properties of calcium channels and their role in neuronal communication. By selectively inhibiting these channels, researchers can study the effects of calcium influx on various cellular processes. This has implications for understanding neurological disorders that involve dysregulation of calcium signaling.

Related Toxins

Structure of AG 505, a related toxin

AG 489 is part of a broader family of agatoxins, which includes other peptides such as AG 505. These toxins share similar structural features and mechanisms of action but may differ in their specific targets or potency. The study of these related toxins provides insights into the diversity of ion channel modulators found in nature.

Related Pages

• Ion channel
• Neurotoxin
• Spider venom
• Calcium channel
• Neurotransmitter