مقالات پذیرفته شده در نهمین کنگره بین المللی زیست پزشکی
Introduction of peptides affecting insect sodium channels from the transcriptome of the venom gland of the scorpion Odontobuthus doriae for the production of biocompatible insecticides
Introduction of peptides affecting insect sodium channels from the transcriptome of the venom gland of the scorpion Odontobuthus doriae for the production of biocompatible insecticides
seyed ilia hejazi,1,*Maryam Naderi Soorki,2
1. Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, 2. Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Introduction: Traditional chemical insecticides, in addition to their side effects on non-target organisms, create problems such as high persistence and environmental pollution. Therefore, discovering safer and more biocompatible insecticides is of great importance. Scorpion venom is one of the natural resources rich in bioactive peptides that specifically target insect Naᵥ channels.
Odontobuthus doriae, a species native to Iran and the Middle East, contains various peptides identified through transcriptomic studies. OD1, one of the most important toxins identified from this scorpion, inhibits the inactivation process of Nav1.7 channels through a specific mechanism, making it a suitable candidate for the development of biocompatible insecticides.
Voltage-gated sodium channels in insects play a crucial role in transmitting nerve signals in the insect nervous system. Many scorpion venom peptides, such as α-ScTx and β-ScTx, selectively block or alter the function of these channels, leading to paralysis or death in insects. α-ScTx toxins inhibit the rapid inactivation process of Naᵥ channels, leading to prolonged sodium influx, depolarization, and neuronal paralysis. Meanwhile, β-ScTx toxins shift the activation threshold of Naᵥ channels, causing abnormal excitation and paralysis. In the following sections, other peptides with similar properties are examined.
Methods: In this study, cDNAs corresponding to ODNaTx2, ODNaTx3, and ODNaTx4 toxins (accession numbers: KU295403, KU295404, KU295405) were selected from the venom gland cDNA library of Odontobuthus doriae, previously constructed by Naderi and colleagues in 2016. These sequences were evaluated structurally and functionally using various bioinformatics software such as NCBI/Blast, UniProt/alignment, Oligo7, DISULFIND, SignalP 4.1, ExPASy/ProtParam, ExPASy/SWISS-MODEL, and Phyre2
Results: cDNA sequence of ODNaTx2, ODNaTx3, and ODNaTx4 toxins after similarity searching by protein blast tools was similar to some α-NaTx toxins from other scorpionsby sufficient identity. Open reading frames of these peptides were 81, 83, and 87, respectively. they also contained three to four intramolecular disulfide bridges, and all of these three putative peptides showed a putative conserved domain belonging to toxin-3 superfamily. According to their pI values, all three peptides exhibit basic characteristics at the isoelectric point. Except for peptide ODNaTx2, peptides ODNaTx3 and ODNaTx4 show a high stability index, and their stable structural features make them promising candidates for biotechnological applications.
Conclusion: he identified peptides, due to their strong sequence, structural, and physicochemical similarities to previously known peptides with selectivity toward insect Naᵥ channels, can play a key role in the development of biocompatible insecticides. Unlike chemical pesticides, the use of these peptides reduces environmental pollution and insect resistance. Thanks to their high biodegradability, they are degraded relatively quickly in the environment and do not cause long-term contamination. Moreover, the unique mechanism of these toxins reduces the likelihood of resistance developing in insect populations compared to chemical insecticides.
However, challenges such as large-scale industrial production, peptide stability and half-life under environmental conditions, and safety assessments in non-target species need to be addressed. Additionally, proteomic studies and protein engineering can optimize peptide structures and enhance their selectivity.