title: Influence of the Length and Charge on the Activity of α-Helical Amphipathic Antimicrobial Peptides.
abstract: Hydrophobic mismatch is important for pore-forming amphipathic antimicrobial peptides, as demonstrated recently [Grau-Campistany, A., et al. (2015) Sci. Rep. 5, 9388]. A series of different length peptides have been generated with the heptameric repeat sequence KIAGKIA, called KIA peptides, and it was found that only those helices sufficiently long to span the hydrophobic thickness of the membrane could induce leakage in lipid vesicles; there was also a clear length dependence of the antimicrobial and hemolytic activities. For the original KIA sequences, the cationic charge increased with peptide length. The goal of this work is to examine whether the charge also has an effect on activity; hence, we constructed two further series of peptides with a sequence similar to those of the KIA peptides, but with a constant charge of +7 for all lengths from 14 to 28 amino acids. For both of these new series, a clear length dependence similar to that of KIA peptides was observed, indicating that charge has only a minor influence. Both series also showed a distinct threshold length for peptides to be active, which correlates directly with the thickness of the membrane. Among the longer peptides, the new series showed activities only slightly lower than those of the original KIA peptides of the same length that had a higher charge. Shorter peptides, in which Gly was replaced with Lys, showed activities similar to those of KIA peptides of the same length, but peptides in which Ile was replaced with Lys lost their helicity and were less active.
authors.affiliation: Department of Chemistry, PROTEO, CGCC, Université Laval , 1045 avenue de la Médecine, Québec, Canada G1V 0A6.|Department of Chemistry, PROTEO, CERMA, CQMF, Université Laval , 1045 avenue de la Médecine, Québec, Canada G1V 0A6.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Gagnon
authors.affiliation: Karlsruhe Institute of Technology (KIT) , Institute of Biological Interfaces (IBG-2), P.O. Box 3640, 76021 Karlsruhe, Germany.
authors.forename: Erik
authors.identifier: 0000-0002-2401-7478
authors.initials: E
authors.lastname: Strandberg
authors.affiliation: Secció de Química Orgànica, Departament de Química Inorgànica i Orgànica, Facultat de Química, Universitat de Barcelona , Barcelona, Spain.
authors.forename: Ariadna
authors.identifier: 0000-0001-8236-9204
authors.initials: A
authors.lastname: Grau-Campistany
authors.affiliation: Karlsruhe Institute of Technology (KIT) , Institute of Biological Interfaces (IBG-2), P.O. Box 3640, 76021 Karlsruhe, Germany.
authors.forename: Parvesh
authors.initials: P
authors.lastname: Wadhwani
authors.affiliation: Karlsruhe Institute of Technology (KIT) , Institute of Biological Interfaces (IBG-2), P.O. Box 3640, 76021 Karlsruhe, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Reichert
authors.affiliation: Karlsruhe Institute of Technology (KIT) , Institute of Biological Interfaces (IBG-2), P.O. Box 3640, 76021 Karlsruhe, Germany.
authors.forename: Jochen
authors.identifier: 0000-0002-2256-9498
authors.initials: J
authors.lastname: Bürck
authors.affiliation: Secció de Química Orgànica, Departament de Química Inorgànica i Orgànica, Facultat de Química, Universitat de Barcelona , Barcelona, Spain.
authors.forename: Francesc
authors.identifier: 0000-0002-4913-155X
authors.initials: F
authors.lastname: Rabanal
authors.affiliation: Department of Chemistry, PROTEO, CERMA, CQMF, Université Laval , 1045 avenue de la Médecine, Québec, Canada G1V 0A6.
authors.forename: Michèle
authors.identifier: 0000-0002-9608-9075
authors.initials: M
authors.lastname: Auger
authors.affiliation: Department of Chemistry, PROTEO, CGCC, Université Laval , 1045 avenue de la Médecine, Québec, Canada G1V 0A6.
authors.forename: Jean-François
authors.identifier: 0000-0003-2412-3083
authors.initials: JF
authors.lastname: Paquin
authors.affiliation: Karlsruhe Institute of Technology (KIT) , Institute of Biological Interfaces (IBG-2), P.O. Box 3640, 76021 Karlsruhe, Germany.|KIT , Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.
authors.forename: Anne S
authors.initials: AS
authors.lastname: Ulrich
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D004912:Erythrocytes / Q000737:chemistry / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008970:Molecular Weight; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D010743:Phospholipids / Q000737:chemistry; D000072756:Protein Conformation, alpha-Helical; D055672:Static Electricity; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; C551483:KIA7 peptide; D008051:Lipid Bilayers; D009842:Oligopeptides; D010743:Phospholipids