title: Prokaryotic expression and antimicrobial mechanism of XPF-St7-derived α-helical peptides.
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.
authors.affiliation: Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China; School of Life Sciences, Jilin University, Changchun, China.
authors.forename: Tonghui
authors.initials: T
authors.lastname: Yi
authors.forename: Yibing
authors.initials: Y
authors.lastname: Huang
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D002463:Cell Membrane Permeability; D004912:Erythrocytes / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D006461:Hemolysis; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013211:Staphylococcus aureus / Q000187:drug effects; D025801:Ubiquitin / Q000096:biosynthesis; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; C000600605:GLLSNVAGLLKQFAKGGVNAVLNPK; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; C000600606:XPF4 peptide; C000600607:XPF6 peptide; D029867:Xenopus Proteins
keywords: XPF-St7; antimicrobial peptide; cell membrane; ubiquitin-tag; α-helical peptide