title: Isolation and characterisation of oncorhyncin II, a histone H1-derived antimicrobial peptide from skin secretions of rainbow trout, Oncorhynchus mykiss.
abstract: A potent antimicrobial peptide, tentatively named oncorhyncin II, was isolated from an acid extract of rainbow trout skin secretions. Amino acid sequencing showed that the first 17 residues of oncorhyncin II are identical to residues 138-154 of histone H1 from rainbow trout. Matrix-assisted laser desorption ionization mass spectrometry revealed that the purified peptide has a molecular mass of 7195.3Da. Taken together, these data indicate that oncorhyncin II is a 69-residue C-terminal fragment of histone H1, probably phosphorylated at two residues. Oncorhyncin II has minimal inhibitory concentrations in the submicromolar range against Gram-(+) as well as Gram-(-) bacteria and it does not display significant haemolytic activity towards trout erythrocytes. The purified peptide was found to induce a marked destabilisation of planar lipid bilayers without the formation of stable ion channels. Oncorhyncin II is possibly a cleavage product of histone H1 with a potentially important role in mucosal defence of rainbow trout.
authors.affiliation: Gatty Marine Laboratory, School of Biology and Medical Science, University of St Andrews, Fife KY16 8LB, Scotland, UK.
authors.forename: Jorge M O
authors.initials: JM
authors.lastname: Fernandes
authors.forename: Gérard
authors.initials: G
authors.lastname: Molle
authors.forename: Graham D
authors.initials: GD
authors.lastname: Kemp
authors.forename: Valerie J
authors.initials: VJ
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006657:Histones / Q000235:genetics*; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000494:pharmacology*; D010743:Phospholipids; D010766:Phosphorylation; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000900:Anti-Bacterial Agents; D006657:Histones; D008051:Lipid Bilayers; D010446:Peptide Fragments; D010743:Phospholipids