Molecular cloning and in silico characterization of knottin peptide, U2-SCRTX-Lit2, from brown spider (Loxosceles intermedia) venom glands

作者：Meissner Gabriel Otto; de Resende Lara Pedro Tulio; Barbour Scott Luis Paulo; Kimus Braz Antonio Sergio; Chaves Moreira Daniele; Matsubara Fernando Hitomi; Soares Eduardo Mendonca; Trevisan Silva Dilza; Gremski Luiza Helena; Veiga Silvio Sanches; Chaim Olga Meiri^*

来源：Journal of Molecular Modeling, 2016, 22(9): 196.

DOI：10.1007/s00894-016-3067-0

• Brown Spider
• ICK
• Insecticide toxin
• Molecular modeling
• Peptide structure
• Venom

Inhibitor cystine knots (ICKs) are a family of structural peptides with a large number of cysteine residues that form intramolecular disulfide bonds, resulting in a knot. These peptides are involved in a variety of biological functions including predation and defense, and are found in various species, such as spiders, scorpions, sea anemones, and plants. The Loxosceles intermedia venom gland transcriptome identified five groups of ICK peptides that represent more than 50 % of toxin-coding transcripts. Here, we describe the molecular cloning of U2-Sicaritoxin-Lit2 (U2-SCRTX-Lit2), bioinformatic characterization, structure prediction, and molecular dynamic analysis. The sequence of U2-SCRTX-Lit2 obtained from the transcriptome is similar to that of mu-Hexatoxin-Mg2, a peptide that inhibits the insect Na-v channel. Bioinformatic analysis of sequences classified as ICK family members also showed a conservation of cysteine residues among ICKs from different spiders, with the three dimensional molecular model of U2-SCRTX-Lit2 similar in structure to the hexatoxin from mu-hexatoxin-Mg2a. Molecular docking experiments showed the interaction of U2-SCRTX-Lit2 to its predictable target-the Spodoptera litura voltage-gated sodium channel (SlNaVSC). After 200 ns of molecular dynamic simulation, the final structure of the complex showed stability in agreement with the experimental data. The above analysis corroborates the existence of a peptide toxin with insecticidal activity from a novel ICK family in L. intermedia venom and demonstrates that this peptide targets Nav channels.

• 出版日期2016-9