title: Parasin I, an antimicrobial peptide derived from histone H2A in the catfish, Parasilurus asotus.
abstract: In response to epidermal injury, Parasilurus asotus, a catfish, secreted a strong antimicrobial peptide into the epithelial mucosal layer. The molecular mass of the antimicrobial peptide, named parasin I, was 2000.4 Da, as determined by matrix-associated laser desorption ionization mass spectrometry. The complete amino acid sequence of parasin I, which was determined by automated Edman degradation, was Lys-Gly-Arg-Gly-Lys-Gln-Gly-Gly-Lys-Val-Arg-Ala-Lys-Ala-Lys-Thr-Arg-Ser- Ser. Eighteen of the 19 residues in parasin I were identical to the N-terminal of buforin I, a 39-residue antimicrobial peptide derived from the N-terminal of toad histone H2A [Kim et al. (1996) Biochem. Biophys. Res. Commun. 229, 381-387], which implies that parasin I was cleaved off from the N-terminal of catfish histone H2A. Parasin I showed strong antimicrobial activity, about 12-100 times more potent than magainin 2, against a wide spectrum of microorganisms, without any hemolytic activity. Circular dichroism spectra of parasin I indicated a structural content of 11% alpha-helix, 33% beta-sheet, and 56% random coils. The beta-sheet axial projection diagram of parasin I showed an amphipathic structure. Our results indicate that the catfish may produce parasin I from its histone H2A by a specific protease upon injury to protect against invasion by microorganisms.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Taejon, South Korea.
authors.forename: I Y
authors.initials: IY
authors.lastname: Park
authors.forename: C B
authors.initials: CB
authors.lastname: Park
authors.forename: M S
authors.initials: MS
authors.lastname: Kim
authors.forename: S C
authors.initials: SC
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D002397:Catfishes; D002942:Circular Dichroism; D004848:Epithelium; D006461:Hemolysis / Q000187:drug effects; D006657:Histones / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009092:Mucous Membrane; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D006657:Histones; D010455:Peptides; C115701:parasin I