title: A novel myotropic peptide from the skin secretions of the tree frog, Polypedates pingbianensis.
abstract: A novel myotropic peptide, polypedatein, was purified and characterized from the skin secretions of the tree frog, Polypedates pingbianensis. Its primary structure, TLLCKYFAIC, was determined by Edman degradation and mass spectrometry. Polypedatein was subjected to bioassays including myotropic, antimicrobial, and serine protease inhibitory activities, which are related with many amphibian skin bioactive peptides. It was found to elicit concentration-dependent contractile effects on isolated rat ileum. cDNA clones encoding the precursor of polypedatein were isolated by screening a skin cDNA library of P. pingbianensis and then sequenced. The amino acid sequence deduced from the cDNA sequences matches well with the result from Edman degradation. BLAST search revealed that the sequence of polypedatein did not show similarity to known protein or peptide sequences. Especially, polypedatein does not contain conserved structural motifs of other amphibian myotropic peptides, such as bradykinins, bombesins, cholecystokinin (CCK), and tachykinins, indicating that polypedatein belongs to a novel amphibian myotropic peptide family. The signal peptide of the precursor encoding polypedatein shows significant sequence identity to that of other amphibian skin defensive peptides, such as antimicrobial peptides, bradykinins, lectins, and serine protease inhibitors, suggesting that polypedatein belongs to a novel amphibian myotropic peptide family. Polypedatein is also the first bioactive peptide from the genus of the frog, Polypedates.
authors.affiliation: Life Sciences College of Nanjing Agricultural University, 1st Weigang, Nanjing, Jiangsu 210095, China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Yan
authors.forename: Lin
authors.initials: L
authors.lastname: Wei
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: He
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.forename: Shilong
authors.initials: S
authors.lastname: Yang
authors.forename: Ren
authors.initials: R
authors.lastname: Lai
authors.forename: Dingqi
authors.initials: D
authors.lastname: Rao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura; D001483:Base Sequence; D003001:Cloning, Molecular; D015723:Gene Library; D007082:Ileum / Q000187:drug effects; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D010802:Phylogeny; D051381:Rats; D012867:Skin / Q000737:chemistry / Q000378:metabolism
chemical_list: D010455:Peptides; C576387:polypedatein peptide, Polypedates pingbianensis