| Primary Identifier | IPR035290 | Type | Family |
| Short Name | Beta/Mu-DGTX-Dc1 |
| description | This family members are 56-59 residue mu-diguetoxin-1 and beta-diguetoxin-1 toxins, which have been isolated from the weaving spider, Diguetia canities. These toxins were isolated as a result of their potent insect paralytic activities, and designated beta-DGTX-Dc1a, mu-DGTX-Dc1b and mu-DGTX-Dc1c (formerly DTX9.2, DTX11 and DTX12) []. Diguetoxin-Dc1a (Dc1a) has been structurally characterised and shown to have disulfide bonds which form a classical inhibitor cysteine knot (ICK) motif in which the Cys13-Cys26 and Cys20-Cys40 disulfide bonds and the intervening sections of the polypeptide backbone form a 23-residue ring that is pierced by the Cys25-Cys54 disulfide bond. This ICK motif is commonly found in spider toxins, and this particular scaffold provides these peptides (so-called knottins) with an unusually high degree of chemical, thermal and biological stability. Dc1a contains an additional disulfide bond (Cys42-Cys52) that appears to serve as a molecular staple which limits the flexibility of a disordered serine-rich hairpin loop. The extended N terminus of Dc1a along with an unusually large loop between Cys26 and Cys40 enables the formation of an N-terminal three-stranded antiparallel β-sheet that is not found in any other knottin. The molecular surface of Dc1a contains a relatively uniform distribution of charged residues; moreover, there are no distinct clusters of hydrophobic residues that might mediate an interaction with lipid bilayers []. |
