title: Isolation, gene expression and solution structure of a novel moricin analogue, antibacterial peptide from a lepidopteran insect, Spodoptera litura.
abstract: An antibacterial peptide was isolated from a lepidopteran insect, Spodoptera litura. The molecular mass of this peptide was determined to be 4489.55 by matrix assisted laser desorption/ionization-time of flight mass (MALDI-TOF MS) spectrometry. The peptide consists of 42 amino acids and the sequence has 69-98% identity to those of moricin-related peptides, antibacterial peptides from lepidopetran insects. Thus, the peptide was designated S. litura (Sl) moricin. Sl moricin showed a broad antibacterial spectrum against Gram-positive and negative bacteria. Sl moricin gene was inducible by bacterial injection and expressed tissue-specifically in the fat body and hemocytes. Furthermore, the solution structure of Sl moricin was determined by two-dimensional (2D) 1H-nuclear magnetic resonance (NMR) spectroscopy and hybrid distance geometry-simulated annealing calculation. The tertiary structure revealed a long alpha-helix containing eight turns along nearly the full length of the peptide like that of moricin, confirming that Sl moricin is a new moricin-like antibacterial peptide. These results suggest that moricin is present not only in B. mori but also in other lepidopteran insects forming a gene family.
authors.affiliation: Biotechnology Research Center, Kubota Corporation, Ryugasaki, Ibaraki 301-0852, Japan. scott.roberts@bbsrc.ac.uk
authors.forename: Yuki
authors.initials: Y
authors.lastname: Oizumi
authors.forename: Hikaru
authors.initials: H
authors.lastname: Hemmi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Minami
authors.forename: Ai
authors.initials: A
authors.lastname: Asaoka
authors.forename: Minoru
authors.initials: M
authors.lastname: Yamakawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D016984:Enterococcus faecium / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000494:pharmacology; D007814:Larva; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012996:Solutions; D018411:Spodoptera / Q000737:chemistry* / Q000235:genetics
chemical_list: D023181:Antimicrobial Cationic Peptides; D019476:Insect Proteins; D011994:Recombinant Proteins; D012996:Solutions; C097209:moricin protein, Bombyx mori