Conserved Site

Conotoxin, alpha-type, conserved site (IPR018072)

Short name: Conotoxin_a-typ_CS


Conotoxin consists of several alpha conotoxin precursor proteins from a number of Conus species. Cone snail toxins, conotoxins, are small peptides with disulphide connectivity, that target ion-channels or G-protein coupled receptors. Based on the number and pattern of disulphide bonds and biological activities, conotoxins can be classified into several families [PMID: 11478951]. Alpha-conotoxins are neurotoxins from the venom of fish-hunting cone snails that block nicotinic acetylcholine receptors (nAChRs) [PMID: 3196703]. Omega, delta and kappa families of conotoxins have a knottin or inhibitor cystine knot scaffold. The knottin scaffold is a very special disulphide through disulphide knot, in which the III-VI disulphide bond crosses the macrocycle formed by two other disulphide bonds (I-IV and II-V) and the interconnecting backbone segments, where I-VI indicates the six cysteine residues starting from the N terminus.

The disulphide bonding network as well as specific amino acids in inter-cysteine loops provide the specificity of conotoxin [PMID: 10988292]. The cysteine arrangement is the same for omega, delta and kappa families, but omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels and kappa conotoxins are potassium channel blockers [PMID: 11478951]. Mu conotoxins have two types of cysteine arrangement, but the knottin scaffold is not observed. Mu conotoxins target the voltage-gated sodium channels [PMID: 11478951] and are useful probes for investigating voltage-dependent sodium channels of excitable tissues [PMID: 2410412]. Alpha conotoxins have two types of cysteine arrangement [PMID: 1390774] and are competitive nicotinic acetylcholine receptor antagonists.

This entry represents the conserved site of Conotoxin.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns