title: A family of antimicrobial peptides related to japonicin-2 isolated from the skin of the chaochiao brown frog Rana chaochiaoensis.
abstract: Four structurally-related peptides with antimicrobial activity were isolated from an extract of the skin of the Chinese brown frog, Rana chaochiaoensis Liu, 1946. Determination of their primary structures revealed that they are members of the japonicin-2 family, previously identified only in the skin of the Japanese brown frog, R. japonica. Japonicin-2CHa (FVLPLLGILPKELCIVLKKNC) represented the most abundant peptide in the extract but its growth-inhibitory potency against Staphylococcus aureus (minimum inhibitory concentration, MIC=100 microM) and Escherichia coli (MIC>100 microM) was appreciably less than that of the more cationic japonicin-2 (FGLPMLSILPKALCILLKRKC). The high degree of structural similarity of japonicin-2CHb (VVPAFVLLKKAICIMLKRNC) with japonicin-2CHc (K9 --> R), and japonicin-2CHd (L16 --> F) is suggestive of recent gene duplication events. The data indicate a close phylogenetic relationship between R. chaochiaoensis and R. japonica but demonstrate that the species are not conspecific.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al-Ain, United Arab Emirates. jmconlon@uaeu.ac.ae
authors.forename: J Michael
authors.initials: JM
authors.lastname: Conlon
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
authors.forename: Hu
authors.initials: H
authors.lastname: Jiansheng
authors.forename: Per F
authors.initials: PF
authors.lastname: Nielsen
mesh_terms: D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D005260:Female; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010455:Peptides; D011898:Ranidae; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D029845:Amphibian Proteins; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C451506:japonicin 2