Pachymedusa dacnicolor tryptophyllin-1: structural characterization, pharmacological activity and cloning of precursor cDNA.
Tryptophyllins are a heterogenous group of amphibian skin peptides originally identified in skin extracts of Neotropical leaf frogs, Phyllomedusa sp., by chemical means. Until now, biosynthetic precursor structure and biological activity remain unreported. Here we describe the isolation of a novel, post-translationally modified tryptophyllin, Lys-Pro-Hyp-Ala-Trp-Val-Pro.amide (PdT-1), from the skin secretion of the Mexican leaf frog, Pachymedusa dacnicolor. Using a 3'- and 5'-RACE strategy and an in vitro skin cDNA library, the PdT-1-encoding precursor was cloned and found to consist of an open-reading frame of 62 amino acids with a single copy of PdT-1 located towards the C-terminus. A synthetic replicate of PdT-1 was found to be a potent myoactive agent, relaxing mammalian arterial smooth muscle and contracting small intestinal smooth muscle at nanomolar concentrations. PdT-1 is thus the first amphibian skin tryptophyllin to be pharmacologically characterized and the first whose precursor cDNA has been cloned.
Chen
Tianbao
T
School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine BT52 1SA, Northern Ireland, UK.
Orr
David F
DF
O'Rourke
Martin
M
McLynn
Ceola
C
Bjourson
Anthony J
AJ
McClean
Stephen
S
Hirst
David
D
Rao
Pingfan
P
Shaw
Chris
C
D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura; D001483:Base Sequence; D001920:Bradykinin / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D012867:Skin / Q000737:chemistry*
D018076:DNA, Complementary; D009842:Oligopeptides; C048291:tryptophyllins; D001920:Bradykinin