Fasciculin 3

Fasciculin 3 is a potent peptide toxin derived from the venom of certain species of elapid snakes, such as the green mamba (Dendroaspis angusticeps). It is a member of the fasciculin family of toxins, which are known for their ability to inhibit acetylcholinesterase (AChE), an enzyme crucial for the breakdown of the neurotransmitter acetylcholine in the synaptic cleft.

Structure and Function

Fasciculin 3 is a small peptide composed of 61 amino acids, with a molecular weight of approximately 7 kDa. The peptide has a three-fingered structure, which is characteristic of many snake venom toxins. This structure allows it to bind tightly to the active site of acetylcholinesterase, thereby inhibiting its activity.

The inhibition of acetylcholinesterase by fasciculin 3 leads to an accumulation of acetylcholine in the synaptic cleft. This results in prolonged stimulation of cholinergic receptors, which can cause continuous muscle contraction and potentially lead to muscle paralysis. This mechanism is similar to that of other acetylcholinesterase inhibitors, such as organophosphates and carbamates, which are used as pesticides and nerve agents.

Biological and Medical Implications

The study of fasciculin 3 and other acetylcholinesterase inhibitors has significant implications for both neuroscience and medicine. Understanding how these toxins interact with acetylcholinesterase can provide insights into the development of new therapeutic agents for conditions such as Alzheimer's disease, where acetylcholinesterase inhibitors are used to enhance cholinergic transmission in the brain.

Additionally, fasciculin 3 serves as a valuable tool in research to study the role of acetylcholine in the nervous system and to develop antidotes for snake venom and other acetylcholinesterase inhibitors.

Also see

• Acetylcholinesterase
• Neurotoxins
• Snake venom
• Elapidae
• Cholinergic system