Alpha-Conotoxin Ac1.1A

**Semantic type:** Hazardous or Poisonous Substance

**Definition:** A 17-amino acid alpha3/5-conotoxin isolated from the venom of the cone snail Conus achatinus that is a competitive antagonist of the muscle-type nicotinic acetylcholine receptors, blocking synaptic transmission at the neuromuscular junction. Alpha-conotoxins are identified by a characteristic arrangement of four-cysteine residues (-CC-C-C-) and disulfide bonding of Cys1-Cys3 and Cys2-Cys4. In addition, alpha3/5-conotoxins are further classified as having three residues in the first intercysteine loop and five residues in the second intercysteine loop.

**Synonyms:** - ALPHA-CONOTOXIN AC1.1A - Alpha-Ac1.1a - Alpha-Ac1.1a