Pathways & interactions
Knottin, scorpion toxin-like superfamily (IPR036574)
Short name: Scorpion_toxin-like_sf
- Defensin, invertebrate/fungal (IPR001542)
- Scorpion short chain toxin, potassium channel inhibitor (IPR001947)
- Scorpion long chain toxin/defensin (IPR002061)
- Knottin, scorpion toxin-like (IPR003614)
- Defensin, plant (IPR008176)
- Short scorpion toxin, potassium channel inhibitor alpha-KTx 8/9 (IPR008911)
- Ergtoxin (IPR012622)
- Defensin, insect (IPR017982)
- Scorpion long chain toxin (IPR018218)
- Termicin (IPR024723)
Knottins are small proteins characterised by a cystine-knot [PMID: 18025039]. They constitute a large family of structurally related peptides with diverse biological functions, including inhibitors, anti-microbial peptides and toxins [PMID: 15551519]. Their structure is composed of a disulfide-bound fold and contains beta-hairpin with two adjacent disulfides.
The scorpion toxin-like domain is found in a subgroup of metazoan knottins mainly from the arthropoda, which include the antibacterial defensins [PMID: 8380707] and the scorpion alpha-neurotoxins [PMID: 12925796]. The plant sequences include members of the gamma-thionin family, which are plant defensins that have no antifungal activity. Other members are insect alpha-amylase inhibitors, cysteine-rich antifungal proteins and proteins annotated as proteinase inhibitors; those that are characterised belong to MEROPS inhibitor family I18, clan I.