Cloning And Expression Of Antibacterial Polypeptides Pexiganan And IB-367 Genes In E.coli

Antibacterial peptide is an important cation polypeptide which is part of non-specific immune system of organisms. It is produced by organisms and has the characteristics of small molecular weight, fast synthesis, rapid diffusability, strong alkalinity, thermo stability, and good solubility. Therefore, Antibacterial peptide is an ideal first line of defense mechanism for organisms. It has the special mechanism against target cells. Antibacterial peptide has broad-spectrum antibacterial activity, some of them even have the activities against viruses, fungi and tumour cell, but they are harmless to normal cells tisues of host..With more and more antibiotic-resistant microorganisms emerging, antibiotic abusee accelerates this process. Antibacterial peptide's mechanism against target cells is remarkably different from that of traditional antibiotics. So they maybe have the potential value become a new generation anti-infection drug.We have synthesized tow antibacterial peptide genes——Pextiganan and IB-367, constructed two plasmids carrying these two genes and selected two strain of bacteria which express this two peptiedes. The antibacterial peptides Pexiganan and IB-367 were expressed in the form of GST fusion proteins in E.coli. The conditions under which strain can produce large amount of soluble fusion proteins were optimized. Fusion proteins were purified by affinity chromatography. They were subsequently cleaved by Factor Xa to obtain Pexiganan and IB-367. Antibacterial testing proved that both Pexiganan and IB-367 have antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.