Gh. Eskandari - PhD Student in Biotechnology, Institute of Molecular Biology, National Academy of Sciences of Armenia, Yerevan, Armenia
A. Jolodar - Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Chaamran Uiversity of Ahvaz, Ahvaz, Iran
Z. Ktsoyan - Laboratory of Molecular Genetics, Institute of Molecular Biology, National Academy of Sciences of Armenia, Yerevan, Armenia
M.R. Seyfiabad Shapouri - Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chaamran Uiversity of Ahvaz, Ahvaz, Iran

The venoms of Buthidae scorpions are known to contain basic, single-chain protein -toxins consisting of ۶۰-۷۰ amino acid residues that are tightly cross-linked by four disulfide bridges. Total RNA was extracted from the venom glands of scorpion Mesobuthus eupeus collected from the Khuzestan province of Iran and then cDNA was synthesized with the modified oligo (dT) primer and extracted total RNA as template. By applying the Semi-nested RT-PCR using homologous primers, the fragments of ۲۷۳ bp was amplified and sequenced. The coding region encodes a polypeptide of ۸۵ amino acid residues with a calculated molecular weight of ۹.۳۳۷ kDa and theoretical isoelectric point of ۶.۵۲. It was designated as MeNaTx-۴. This peptide with homology to the "Scorpion long chain toxin-like domain" is belongs to the Toxin-۳ superfamily. Multiple alignment of the putative amino acid sequence of MeNaTx-۴ exhibited ۹۵% sequence identity with lesser Asian scorpion M. eupeus venom sodium channel -toxin-۳ but interestingly displayed only ۶۳% identity with other -toxins from this species. The sequence was also identical to the counterpart sequences from M. martensii (۹۲%) and Buthus occitanus israelis (۸۰%). This high sequence similarity together with completely conserved in the positions of all ۸ Cys indicated that MeNaTx-۴ is a new member of -toxin from the Iranian M. eupeus which may originate from a common ancestor.

, Toxin, Semi, nested RT, PCR, Scorpion venom, Mesobuthus eupeus