Prokaryotic expression and antimicrobial mechanism of XPF‐St7‐derived α‐helical peptides |
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| Authors: | Tonghui Yi Yibing Huang Yuxin Chen |
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| Institution: | 1. Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China;2. School of Life Sciences, Jilin University, Changchun, China;3. National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, China |
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| Abstract: | XPF‐St7 (GLLSNVAGLLKQFAKGGVNAVLNPK) is an antimicrobial peptide isolated from Silurana tropicalis. We developed an α‐helical segment of XPF‐St7 termed as XPF2. Using the XPF2 as a framework, we increased the positive net charge of XPF2 by amino acid substitutions, and thus obtained two novel antimicrobial peptides XPF4 and XPF6. These were each fused with an ubiquitin tag and successfully expressed in Escherichia coli. This ubiquitin fusion system may present a viable alternative for industrial production of antimicrobial peptides. XPF4 and XPF6 showed much better overall antimicrobial activity against both Gram‐negative and Gram‐positive bacteria than XPF2. The therapeutic index of XPF4 and XPF6 was 5.6‐fold and 6.7‐fold of XPF2, respectively. Bacterial cell membrane permeabilization and genomic DNA interaction assays were utilized to explore the mechanism of action of XPF serial peptides. The results revealed that the target of these antimicrobial peptides was the bacterial cytoplasmic membrane. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. |
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| Keywords: | XPF‐St7 antimicrobial peptide α ‐helical peptide ubiquitin‐tag cell membrane |
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