Finding a safe strategy for targeting tumor cells without affecting normal cells is one of the goals of cancer treatment. scorpion venoms are rich sources of biologically active peptides which some of them have cancer therapy potency. we identify a bifunctional peptide with carboxypeptidase inhibitory activity form the iranian scorpion “odontobutus doriae” venom gland and create a framework to access for sufficient amounts of this peptide for cancer related researches.
Methods
A cdna library was constructed from venom gland transcriptome of 6 scorpions. library was screened by culturing of the liquid library on lb-agar plates. analysis of positive clones was performed by plasmid extraction and sequencing of inserts. the cdna encoding odontobuthus doriae venom peptide5 (odvp5) was isolated from library and its putative peptide characterized by some bioinformatics software such as blastp, signalp4.0, disulfind, clustal omega, modeling software and so on.
Results
Characterization of odvp5 after detection and deletion of a 21 residue signal peptide showed that mature odvp5 has 59 amino acid residue and have 3 disulfide bond. molecular weight and theoretical pi is 6694.6 and 8.97 respectively. due to open reading frame (orf) sequence similarity and homologous alignment results, odvp5 was so similar to kunitz-type carboxypeptidase inhibitor kci-4 from black fat–tailed scorpion “androctonus bicolor” by the highest score.
Conclusion
Considering the role of carboxypeptidases in cancer progression and tumorigenesis, finding inhibitory peptides like odvp5, for blocking of the peptidase activity in tumor cells, is one the ways to prevent and treat cancer.
Keywords
Cdna library, carboxypeptidase inhibitor , cancer therapy, iranian scorpion transcriptome
