title: Augmentation of the antimicrobial activities of guinea pig cathelicidin CAP11-derived peptides by amino acid substitutions.
abstract: Mammalian myeloid and epithelial cells express various peptide antibiotics (such as defensin and cathelicidin) that contribute to the innate host defense against invading microorganisms. Among these, guinea pig cathelicidin CAP11 (G1-I43) possesses potent antibacterial activities against Gram-positive and -negative bacteria, and also lipopolysaccharide-neutralizing activity. We previously revealed that the active region with antibacterial activity is localized at G1 to R18 of CAP11. In this study, to develop peptide derivatives with enhanced antimicrobial actions, we utilized the amphipathic 18-mer peptide (G1-R18) as a template. Anti-microbial activities of the peptides were assessed by alamarBlue assay (Escherichia coli, Staphylococcus aureus and Candida albicans) and colony formation assay (Porphyromonas gingivalis). Furthermore, the membrane-permeabilization activities were determined by using E. coli ML-35p as a target. By substituting K5, T9, R10, R12, and G17 with five L residues, the hydrophobicity of the peptide (1-18m1) was increased, and by substituting G1, and Q14 with K and R residues, respectively, the hydrophilicity (positive charge) of the peptide (1-18m2) was enhanced. Among the peptides, 1-18m2 exhibits the most potent antimicrobial and membrane-permeabilizing activities against the microorganisms examined. Thus, the antimicrobial activities of the amphipathic CAP11-derived 18-mer peptide can be augmented by modifying its hydrophobicity and hydrophilicity (positive charge), and 1-18m2 is the most potent among the peptide derivatives with therapeutic potential for Gram-positive and -negative bacterial, and fungal infections.
authors.affiliation: Department of Host Defense and Biochemical Research, Juntendo Univesrity School of Medicine, 2-1-1 Hongo, Tokyo 113-8421, Japan.
authors.forename: Daiju
authors.initials: D
authors.lastname: Okuda
authors.forename: Shin
authors.initials: S
authors.lastname: Yomogida
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kuwahara-Arai
authors.forename: Keiichi
authors.initials: K
authors.lastname: Hitamatsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tamura
authors.forename: Isao
authors.initials: I
authors.lastname: Nagaoka
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D002463:Cell Membrane Permeability / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D006168:Guinea Pigs; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D019897:Periplasm / Q000187:drug effects / Q000201:enzymology; D017386:Sequence Homology, Amino Acid; D001616:beta-Galactosidase / Q000378:metabolism; D001618:beta-Lactamases / Q000378:metabolism; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; C440609:CAP11 protein, Cavia; D010455:Peptides; D001616:beta-Galactosidase; D001618:beta-Lactamases; D054804:Cathelicidins