12 Explain how a conformation change in the channel complex

12. Explain how a conformation change in the channel complex might lead to tighter interactions between the TTX and the channel.

Solution

Answer:

Tetrodotoxin (TTX) is a potent marine neurotoxin, named after the order of fish from which it is most commonly associated with, the tetraodon pufferfish.

TTX specifically acts by blocking voltage-gated sodium channels on the surface of neurons. TTX consists of a guanidinium group and a pyrimidine ring with other associated fused ring systems. TTX resembles the hydrated sodium ion conformation, enters the mouth of the Na⁺- Channel peptide complex and binds to a peptide glutamate side group.

In the second half of the binding event, the peptide changes its conformation. This further tightens its hold on the Na⁺- Channel peptide complex. Following complex conformational changes, TTX is further electrostatically attached to the opening of the Na+ gate channel.