title: A novel defensin-like antimicrobial peptide from the skin secretions of the tree frog, Theloderma kwangsiensis.
abstract: Defensins are one of the major families of antimicrobial peptides (AMPs), and have been reported from prokaryotic to eukaryotic kingdoms. But defensins are seldom found in amphibian which is a major resource of novel AMPs. A novel defensin-like AMP (defensin-TK) was isolated and characterized from skin secretions of the tree frog Theloderma kwangsiensis. The cDNA encoding defensin-TK precursor was cloned from the skin cDNA library of T. kwangsiensis. The deduced precursor of defensin-TK was composed of three domains, a signal peptide of 16 residues, a spacer peptide of 1 residues and a mature peptide of 42 residues. The mature peptide of defensin-TK shared the highest identity with the salamander (Cynops fudingensis) defensin CFBD-1. The six conserved cysteines which formed intramolecular disulfide bonds of defensins also exist in defensin-TK. Phylogenetic analysis indicated that defensin-TK was closely related to fish β-defensins. Defensin-TK showed potent and broad-spectrum antimicrobial activity. In addition, defensin-TK exerted a low hemolytic activity on human red cells. These results suggested defensin-TK might play an important role in defense the skin pathogenic microbes of tree frog T. kwangsiensis, and might be a promising candidate for development of novel antimicrobial agents.
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China; Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang 316000, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Shen
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Yao
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China.
authors.forename: Canwei
authors.initials: C
authors.lastname: Du
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Luan
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China. Electronic address: yanxw@njau.edu.cn.
authors.forename: Xiuwen
authors.initials: X
authors.lastname: Yan
mesh_terms: D029845:Amphibian Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D018076:DNA, Complementary; D023082:Defensins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011898:Ranidae / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000378:metabolism* / Q000382:microbiology; D014562:Caudata / Q000235:genetics / Q000378:metabolism
chemical_list: D029845:Amphibian Proteins; D018076:DNA, Complementary; D023082:Defensins; D011498:Protein Precursors; D021382:Protein Sorting Signals
keywords: Amphibian; Antimicrobial peptide; Defensin; Skin secretion; Theloderma kwangsiensis