addition the homodimer acquires the capacity to block α-3/β-2 nAChRs. Bioinformatics and reactivity The sequence of α-cobratoxin is: IRCFITPDITSKDCPNGHVCYTKTWCDAFCSIRGKRVDLGCAATCPTVKTGVDIQCCSTDNCNPFPTRKRP The venom has different aminoacids that are able to bind reactively to the acetylcholine receptors. These receptors can bind different ligands like acetylcholine, nicotine and cobratoxin. Lysine, K at position 23 binds selectively to Torpedo AChR (Acetylcholine receptor). The aminoacids that bind to both neuronal and Torpedo AChRs are tryptophan at position 25, aspartic acid at 27, phenylalanine at 29, arginine at 33 and 36 and phenylalanine at 65. The aminoacids responsible for the binding to alpha-7 AChR are cysteine at 26 and 30, alanine at 28 and lysine at positions 35 and 49. Mode of action α-Cobratoxin binds antagonistically and slowly reversible to muscle-type and neuronal type nAChRs. This bond will block the receptor's ability to bind acetylcholine and thereby inhibits the ion flow through the postsynaptic membrane, which will lead to paralysation. nAChRs can obtain their open conformation by a twist-like motion as seen in figure X. But this opening would only last up to 3 ms, which is too short for initiating an ion-flux. When acetylcholine binds to the receptor it remains in the open conformation for a longer period which is sufficient to cause the ion-flux. When a complex was formed with an α7 receptor-like protein(AChBP-complex) and 5 α-Cobratoxins, it is not able to twist anymore. Cobratoxin binds to the ligand-binding pocket between the α/γ or α/δ nAChR subunits. It causes a postsynaptic block at the NMJ nAChRs by preventing the binding of acetylcholine to its receptor. Long neurotoxins like Cobratoxin also block neuronal α7 nAChRs, but it is unclear how effectively the long neurotoxin can reach the central nervous system (CNS). Indications Indications for the bite of a cobra, in this case the Naja atra (Chinese cobra) are the darkening of the bite wound and pain and swelling of the area around it. Necrosis is a very severe result of the snake bite, and can keep harming the victim for years after the attack. Of course the Chinese cobra is only one of the snakes that produce cobratoxin, but the other snakes cause similar indications. Effects The cobratoxin of the Thailand cobra belongs to the neurotoxins. An important property of neurotoxins is that they are not usually able to cross the blood-brain barrier. Instead of this, they block the nerve transmission in the body. α-Cobratoxin is