title: Effects of the hinge region of cecropin A(1-8)-magainin 2(1-12), a synthetic antimicrobial peptide, on liposomes, bacterial and tumor cells.
abstract: A 20-residue hybrid peptide (CA(1-8)-MA(1-12): KWKLFKKIGIGKFLHSAKKF-NH(2)) incorporating 1-8 residues of cecropin A (CA) and 1-12 residues of magainin 2 (MA) has potent antibiotic activity without hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly of CA(1-8)-MA(1-12) (CA-MA) on antibiotic activity, CA-MA and its three analogues, CA-MA1, CA-MA2 and CA-MA3 were synthesized. The Gly-Ile-Gly sequence of CA-MA was deleted in CA-MA1 and replaced with Pro and Gly-Pro-Gly in CA-MA2 and CA-MA3, respectively. CA-MA1 and CA-MA3 caused a significant decrease in the bactericidal rate against Escherichia coli and Bacillus subtilis and the tumoricidal activity against four different tumor cells, and the PC/PS (4:1, w/w) vesicle-aggregating and disrupting activities. However, CA-MA2 showed a similar bactericidal rate and antitumor, vesicle-aggregating and disrupting activities, as compared with CA-MA. These results suggested that the flexibility or beta-turn induced by Gly-Ile-Gly or Pro in the central part of CA-MA may be important in the electrostatic interaction of the cationic short alpha-helical region in the N-terminus with the cell membrane surface and the hydrophobic interaction of amphipathic alpha-helical region in the C-terminus with the hydrophobic acyl chains in the cell membrane. CA-MA3 exhibited lower activity in antibacterial, antitumor, and vesicle-aggregating and disrupting activities than CA-MA and CA-MA2. This result suggested that the excessive beta-turn structure by Gly-Pro-Gly in CA-MA3 seems to interrupt the ion channel/pore formation on the lipid bilayer. It was concluded that the appropriate flexibility or beta-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.
authors.affiliation: Peptide Engineering Research Unit, Korea Research Institute of Bioscience and Biotechnology, P.O. Box 115, Yusong, Taejon, South Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Shin
authors.forename: J H
authors.initials: JH
authors.lastname: Kang
authors.forename: S Y
authors.initials: SY
authors.lastname: Jang
authors.forename: Y
authors.initials: Y
authors.lastname: Kim
authors.forename: K L
authors.initials: KL
authors.lastname: Kim
authors.forename: K S
authors.initials: KS
authors.lastname: Hahm
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D023181:Antimicrobial Cationic Peptides; D001412:Bacillus subtilis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D019169:Jurkat Cells; D008081:Liposomes; D051379:Mice; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012486:Salmonella typhimurium / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013297:Streptococcus pyogenes / Q000187:drug effects; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D008081:Liposomes; D010455:Peptides; C121751:cecropin A(1-8)magainin 2(1-12)