title: Structure-activity relationships of the antimicrobial peptide arasin 1 - and mode of action studies of the N-terminal, proline-rich region.
abstract: Arasin 1 is a 37 amino acid long proline-rich antimicrobial peptide isolated from the spider crab, Hyas araneus. In this work the active region of arasin 1 was identified through structure-activity studies using different peptide fragments derived from the arasin 1 sequence. The pharmacophore was found to be located in the proline/arginine-rich NH(2) terminus of the peptide and the fragment arasin 1(1-23) was almost equally active to the full length peptide. Arasin 1 and its active fragment arasin 1(1-23) were shown to be non-toxic to human red blood cells and arasin 1(1-23) was able to bind chitin, a component of fungal cell walls and the crustacean shell. The mode of action of the fully active N-terminal arasin 1(1-23) was explored through killing kinetic and membrane permeabilization studies. At the minimal inhibitory concentration (MIC), arasin 1(1-23) was not bactericidal and had no membrane disruptive effect. In contrast, at concentrations of 5×MIC and above it was bactericidal and interfered with membrane integrity. We conclude that arasin 1(1-23) has a different mode of action than lytic peptides, like cecropin P1. Thus, we suggest a dual mode of action for arasin 1(1-23) involving membrane disruption at peptide concentrations above MIC, and an alternative mechanism of action, possibly involving intracellular targets, at MIC.
authors: Norwegian College of Fishery Science, University of Tromsø, Tromsø, Norway.
authors: Victoria S
authors: VS
authors: Paulsen
authors: Hans-Matti
authors: HM
authors: Blencke
authors: Monica
authors: M
authors: Benincasa
authors: Tor
authors: T
authors: Haug
authors: Jacobus J
authors: JJ
authors: Eksteen
authors: Olaf B
authors: OB
authors: Styrvold
authors: Marco
authors: M
authors: Scocchi
authors: Klara
authors: K
authors: Stensvåg
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002686:Chitin / Q000378:metabolism; D002942:Circular Dichroism; D004926:Escherichia coli / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D055232:Proline-Rich Protein Domains; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D010446:Peptide Fragments; D010455:Peptides; C528380:arasin 1, Hyas araneus; D002686:Chitin; C070016:cecropin P1-LI