title: Bi-functional peptides with both trypsin-inhibitory and antimicrobial activities are frequent defensive molecules in Ranidae amphibian skins.
abstract: Amphibian skins act as the first line against noxious aggression by microorganisms, parasites, and predators. Anti-microorganism activity is an important task of amphibian skins. A large amount of gene-encoded antimicrobial peptides (AMPs) has been identified from amphibian skins. Only a few of small protease inhibitors have been found in amphibian skins. From skin secretions of 5 species (Odorrana livida, Hylarana nigrovittata, Limnonectes kuhlii, Odorrana grahami, and Amolops loloensis) of Ranidae frogs, 16 small serine protease inhibitor peptides have been purified and characterized. They have lengths of 17-20 amino acid residues (aa). All of them are encoded by precursors with length of 65-70 aa. These small peptides show strong trypsin-inhibitory abilities. Some of them can exert antimicrobial activities. They share the conserved GCWTKSXXPKPC fragment in their primary structures, suggesting they belong to the same families of peptide. Signal peptides of precursors encoding these serine protease inhibitors share obvious sequence similarity with those of precursors encoding AMPs from Ranidae frogs. The current results suggest that these small serine protease inhibitors are the common defensive compounds in frog skin of Ranidae as amphibian skin AMPs.
authors.affiliation: Life Sciences College of Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China.
authors.forename: Xiuwen
authors.initials: X
authors.lastname: Yan
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.forename: Xuening
authors.initials: X
authors.lastname: Yang
authors.forename: Qiaolin
authors.initials: Q
authors.lastname: Che
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.forename: Hailong
authors.initials: H
authors.lastname: Yang
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Liu
authors.forename: Dewen
authors.initials: D
authors.lastname: You
authors.forename: Aili
authors.initials: A
authors.lastname: Wang
authors.forename: Jianxu
authors.initials: J
authors.lastname: Li
authors.forename: Ren
authors.initials: R
authors.lastname: Lai
mesh_terms: D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000737:chemistry; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D007113:Immunity, Innate; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011898:Ranidae; D016415:Sequence Alignment; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012867:Skin / Q000737:chemistry* / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D029845:Amphibian Proteins; D023181:Antimicrobial Cationic Peptides; D010455:Peptides; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; D014357:Trypsin