title: Molecular cloning of novel antimicrobial peptide genes from the skin of the Chinese brown frog, Rana chensinensis.
abstract: One species of the Chinese brown frog, Rana chensinensis, is widely distributed in north-central China. In this study, a cDNA library was constructed to clone the antimicrobial peptides' genes from the skin of R. chensinensis. Twenty-three prepropeptide cDNA sequences encoding twelve novel mature antimicrobial peptides were isolated and characterized. Six peptides belonged to three known families previously identified from other Ranid frogs: temporin (4 peptides), brevinin-2 (1 peptide), and palustrin-2 (1 peptide). The other six peptides showed little similarity to known antimicrobial peptides. According to the amino acid sequences, with or without α-helix structure, and either hydrophilic or hydrophobic, these were organized into four new families: chensinin-1 (3 peptides), chensinin-2 (1 peptide), chensinin-3 (1 peptide), and chensinin-4 (1 peptide). Five peptides from different families were chemically synthesized, and their antimicrobial, cytolytic, and hemolytic activities were evaluated. Of these, brevinin-2CE showed strongest antimicrobial activities against both the Gram-positive and Gram-negative bacteria with a slight hemolysis. Temporin-1CEe and palustrin-2CE also displayed a slight hemolysis, but they had different activities to prokaryotic cells. Temporin-1CEe showed higher antimicrobial activity against Gram-positive bacteria than Gram-negative bacteria, whereas it was contrary to palustrin-2CE. Chensinin-1 CEb and chensinin-3CE only had moderate antimicrobial activity against microorganisms. In addition, the brevinin-2 peptides from different brown frogs were analyzed to reveal the taxonomy and phylogenetic relationships of R. chensinensis.
authors.affiliation: College of Life Sciences, Shaanxi Normal University, Xi'an 710062, Shaanxi, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Su
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D015723:Gene Library; D008969:Molecular Sequence Data; D010802:Phylogeny; D011898:Ranidae / Q000235:genetics / Q000378:metabolism*; D012867:Skin / Q000378:metabolism*
chemical_list: D023181:Antimicrobial Cationic Peptides