Recombinant scorpine produced using SUMO fusion partner in Escherichia coli has the activities against clinically isolated bacteria and inhibits the Plasmodium falciparum parasitemia in vitro.

Chao Zhang,Qi Gao,Yaping Gu,Huayun Zhou,Xinlong He,Jun Cao

doi:10.1371/journal.pone.0103456

Abstract

Scorpine, a small cationic peptide from the venom of Pandinus imperator, which has been shown to have anti-bacterial and anti-plasmodial activities, has potential important applications in the pharmaceutical industries. However, the isolation of scorpine from natural sources is inefficient and time-consuming. Here, we first report the expression and purification of recombinant scorpine in Escherichia coli, using small ubiquitin-related modifier (SUMO) fusion partner. The fusion protein was expressed in soluble form in E. coli, and expression was verified by SDS-PAGE and western blotting analysis. The fusion protein was purified to 90% purity by nickel–nitrilotriacetic acid (Ni2+–NTA) resin chromatography. After the SUMO-scorpine fusion protein was cleaved by the SUMO protease, the cleaved sample was reapplied to a Ni2+–NTA column. Tricine/SDS-PAGE gel results indicated that Scorpine had been purified successfully to more than 95% purity. The recombinantly expressed Scorpine showed anti-bacterial activity against two standard bacteria including Staphylococcus aureus ATCC 29213 and Acinetobacter baumannii ATCC 19606, and clinically isolated bacteria including S. aureus S, S. aureus R, A. baumannii S, and A. baumannii R. It also produced 100% reduction in Plasmodium falciparum parasitemia in vitro. Thus, the expression strategy presented in this study allowed convenient high yield and easy purification of recombinant Scorpine for pharmaceutical applications in the future.

Highlights

The oldest known scorpions lived around 430 million years ago in the Silurian period, on the bottom of shallow tropical seas, regarded as the oldest terrestrial arthropods [1]
Scorpions are a rich source of antimicrobial peptides: (1) androctonin isolated from the hemolymph of Androctonus australis, shows marked sequence similarity to tachyplesins, polyphemusins and gomesin [3,4]; (2) hadrurin from the venom of Hadrurus aztecus, which is hemolytic [5]; (3) opistoporin-1, which possesses hemolytic activity, and opistoporin-2, both from the venom of the South African scorpion Opistophtalmus carinatus [6]; (4) scorpine, which is the subject of this study, arising from the venom of Pandinus imperator, was shown to have anti-bacterial and anti-plasmodial activity in vitro[7], and has shown a potent toxic effect on sexual and asexual stages of Plasmodium berghei and Plasmodium falciparum, respectively, and a strong inhibition of dengue 2 virus (DENV-2) infection[8]
Among the peptides isolated from the venom of the African scorpion Pandinus imperator, a molecule, named Scorpine, was identified [7], showing antibacterial and anti-plasmodial activities [7,8], with the possibility of being used as an anti-microbial and anti-plasmodial agent in the future

Summary

Introduction

The oldest known scorpions lived around 430 million years ago in the Silurian period, on the bottom of shallow tropical seas, regarded as the oldest terrestrial arthropods [1]. Scorpion venoms consist of a complex of several toxins that exhibit a wide range of biological properties and actions, as well as chemical compositions, toxicity, pharmacokinetic, and pharmacodynamic characteristics [2]. Scorpions are a rich source of antimicrobial peptides: (1) androctonin isolated from the hemolymph of Androctonus australis, shows marked sequence similarity to tachyplesins, polyphemusins and gomesin [3,4]; (2) hadrurin from the venom of Hadrurus aztecus, which is hemolytic [5]; (3) opistoporin-1, which possesses hemolytic activity, and opistoporin-2, both from the venom of the South African scorpion Opistophtalmus carinatus [6]; (4) scorpine, which is the subject of this study, arising from the venom of Pandinus imperator, was shown to have anti-bacterial and anti-plasmodial activity in vitro[7], and has shown a potent toxic effect on sexual and asexual stages of Plasmodium berghei and Plasmodium falciparum, respectively, and a strong inhibition of dengue 2 virus (DENV-2) infection[8]. Scorpine’s wide range of activities provides the possibility that scorpine can be used as an antimicrobial and anti-plasmodial agent in the future

Methods

Results

Conclusion