Prokaryotic Expression and Purification of κ-SLPTX-Ssm2e, a Candidate Insecticide from Centipede Scolopendra subspinipes mutilans
YAO Meng;ZHAO Dan;LIU Chang-jun;WANG Gan;WU Lei;Research Center of Biological Information, College of Science, National University of Defense Technology;
The toxin κ-SLPTX-Ssm2e, from centipede Scolopendra subspinipes mutilans, is highly homologous with a known insecticidal toxin κ-SLPTX-Ssm2a. It is composed of 31 amino acid residues and three pairs of disulfide bonds. In order to explore its structure and functions, the method of prokaryotic expression was adopted to obtain abundant toxins. The recombinant protein GST-SUMO-κ-SLPTX-Ssm2e was expressed in E. coli BL21(DE3) by auto-induction, purified by GST affinity chromatography and digested by the Ulp1 protease to release target toxin, which was further purified by reverse-phase high performance liquid chromatography(RP-HPLC). Through the MALDI-TOF/TOF mass spectrum assay, the relative molecular mass of the polypeptide molecule was demonstrated to be 3 475.732, identical to the theoretical value 3 475.07.The research lays the foundation for further study of the insecticidal activity of κ-SLPTX-Ssm2e.