Molecular Cloning of a Novel Bradykinin-Related Peptide from the Skin of Indian Bronzed Frog Hylarana Temporalis

Bradykinin-related peptides (BRPs) constitute one of the most studied groups of bioactive peptides in amphibian skin secretions. The present study describes the successful isolation of a novel BRP (hylaranakinin TE) from the skin secretion of the Indian bronzed frog Hylarana temporalis. The deduced open reading frame consisted of 115 amino acid residues with a putative signal peptide of 22 amino acid residues, followed by a spacer region and mature peptide regions that encode for two BRPs: a canonical bradykinin R-9-R with a C-terminal extension of FVPASSL and Thr6-BK. The Thr6-BK reported in the present study had an unusual FP-insertion in the N-terminal part and ended in FAPEII, which is very different from the IAPAIV sequence reported in other ranid frogs. Unlike the mammalian bradykinin and its precursor, amphibian BRPs and their precursors are extremely variable, as evident from the present study. This forms the first report of BRPs from Hylarana temporalis, endemic to India and Sri Lanka.