title: Two novel families of antimicrobial peptides from skin secretions of the Chinese torrent frog, Amolops jingdongensis.
abstract: The characterization of new natural antimicrobial peptides (AMPs) can help to solve the serious problem of bacterial resistance to currently used antibiotics. In the current study, we analyzed two families of AMPs from the Chinese torrent frog Amolops jingdongensis with a range of bioactivities. The first family of peptides, named jindongenin-1a, is 24 amino acids in length; a BLAST search of jindongenin-1a revealed no sequence similarity with other AMPs. The second family consists of two peptides containing 29 amino acid residues each. These peptides have high sequence similarity with the AMPs of palustrin-2 and are therefore designated palustrin-2AJ1 and palustrin-2AJ2. The cDNA sequences encoding these AMPs have been cloned and the deduced protein sequence of each AMP has been determined by protein sequencing. Sequence and structural analysis showed that each precursor is composed of a putative signal peptide, an N-terminal spacer, a processing site and a disulfide-bridged heptapeptide segment at the C-terminus. We synthesized jindongenin-1a and palustrin-AJ1 to test their antimicrobial, hemolytic, antioxidative and cytotoxic activities. These two peptides showed broad-spectrum antimicrobial activity to standard and clinically isolated strains of bacteria. In addition, they exhibited weak hemolytic activity to human and rabbit erythrocytes under our experimental conditions. Moreover, these peptides also displayed cytotoxic activity against the K562 and HT29 mammalian cell lines and low anti-oxidant activity. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents.
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming 650223, Yunnan, China.
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Chen
authors.forename: Xinwang
authors.initials: X
authors.lastname: Yang
authors.forename: Zichao
authors.initials: Z
authors.lastname: Liu
authors.forename: Lin
authors.initials: L
authors.lastname: Zeng
authors.forename: Wenhui
authors.initials: W
authors.lastname: Lee
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002681:China; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004912:Erythrocytes / Q000187:drug effects; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D019073:HT29 Cells; D006801:Humans; D020014:K562 Cells; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D011817:Rabbits; D011898:Ranidae / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D021382:Protein Sorting Signals