Three-finger toxin
| Snake toxin and toxin-like protein | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Erabutoxin A, a neurotoxin that is a member of the 3FTx superfamily. The three "fingers" are labeled I, II, and III, and the four conserved disulfide bonds are shown in yellow. Rendered from PDB: 1QKD. | |||||||||
| Identifiers | |||||||||
| Symbol | Toxin_TOLIP | ||||||||
| Pfam | PF00087 | ||||||||
| Pfam clan | CL0117 | ||||||||
| InterPro | IPR003571 | ||||||||
| PROSITE | PS00272 | ||||||||
| CATH | 1qkd | ||||||||
| SCOP2 | 1qkd / SCOPe / SUPFAM | ||||||||
| OPM superfamily | 53 | ||||||||
| OPM protein | 1txa | ||||||||
| CDD | cd00206 | ||||||||
| |||||||||
Three-finger toxins (abbreviated 3FTx) are a protein superfamily of small toxin proteins found in the venom of snakes. Three-finger toxins are in turn members of a larger superfamily of three-finger protein domains which includes non-toxic proteins that share a similar protein fold. The group is named for its common structure consisting of three beta strand loops connected to a central core containing four conserved disulfide bonds. The 3FP protein domain has no enzymatic activity and is typically between 60 and 74 amino acid residues long. Despite their conserved structure, three-finger toxin proteins have a wide range of pharmacological effects. Most members of the family are neurotoxins that act on cholinergic intercellular signaling; the alpha-neurotoxin family interacts with muscle nicotinic acetylcholine receptors (nAChRs), the kappa-bungarotoxin family with neuronal nAChRs, and muscarinic toxins with muscarinic acetylcholine receptors (mAChRs).