Janus-Faced Atracotoxin, a Blocker of Insect Potassium Channels

The Janus-faced atracotoxins are a family of insect-specific excitatory neurotoxins isolated from the venom of Australian funnel-web spiders. In addition to a strikingly asymmetric distribution of charged residues, from which their name is derived, they contain an extremely rare vicinal disulfide bond which is essential for neurotoxic activity. The toxins are selective for insect voltage-gated potassium channels. Alanine-scanning mutagenesis revealed that the bioactive surface comprises a bipartite surface patch, shown in yellow and red, on one face of the toxin.

Wang, X-H., Connor, M., Smith, R., Maciejewski, M.W., Howden, M.E.H., Nicholson, G. M., Christie, M. J. and King, G. F. (2000) Discovery and characterization of a family of insecticidal neurotoxins with a rare vicinal disulfide bond. Nature Structural Biology 7, 505-513.

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