2NDI
Solution structure of the toxin ISTX-I from Ixodes scapularis
Summary for 2NDI
| Entry DOI | 10.2210/pdb2ndi/pdb |
| NMR Information | BMRB: 26062 |
| Descriptor | Putative secreted salivary protein (1 entity in total) |
| Functional Keywords | toxin peptide, toxin |
| Biological source | Ixodes scapularis (blacklegged tick,deer tick,shoulder tick) |
| Total number of polymer chains | 1 |
| Total formula weight | 4793.28 |
| Authors | |
| Primary citation | Rong, M.,Liu, J.,Zhang, M.,Wang, G.,Zhao, G.,Wang, G.,Zhang, Y.,Hu, K.,Lai, R. A sodium channel inhibitor ISTX-I with a novel structure provides a new hint at the evolutionary link between two toxin folds. Sci Rep, 6:29691-29691, 2016 Cited by PubMed Abstract: Members of arachnida, such as spiders and scorpions, commonly produce venom with specialized venom glands, paralyzing their prey with neurotoxins that specifically target ion channels. Two well-studied motifs, the disulfide-directed hairpin (DDH) and the inhibitor cystine knot motif (ICK), are both found in scorpion and spider toxins. As arachnids, ticks inject a neurotoxin-containing cocktail from their salivary glands into the host to acquire a blood meal, but peptide toxins acting on ion channels have not been observed in ticks. Here, a new neurotoxin (ISTX-I) that acts on sodium channels was identified from the hard tick Ixodes scapularis and characterized. ISTX-I exhibits a potent inhibitory function with an IC50 of 1.6 μM for sodium channel Nav1.7 but not other sodium channel subtypes. ISTX-I adopts a novel structural fold and is distinct from the canonical ICK motif. Analysis of the ISTX-I, DDH and ICK motifs reveals that the new ISTX-I motif might be an intermediate scaffold between DDH and ICK, and ISTX-I is a clue to the evolutionary link between the DDH and ICK motifs. These results provide a glimpse into the convergent evolution of neurotoxins from predatory and blood-sucking arthropods. PubMed: 27407029DOI: 10.1038/srep29691 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
Download full validation report
