The Bowman-Birk (BBI) family of protease inhibitors is a prototype group found mainly in plants, particularly grasses and legumes, which have been subjected to decades of study. However, the discovery of attenuated peptides containing the canonical Bowman-Birk protease inhibitory motif, has recently been reported from amphibian skin secretions, mostly from members of the family Ranidae. Their roles in amphibian defence have been proposed as working cooperatively with antimicrobial peptides and reducing peptide degradation. A novel trypsin inhibitory peptide, named livisin, was found in the skin secretion of the green cascade frog, Odorrana livida. Its biosynthetic precursor-encoding cDNA was cloned using a RACE strategy and the predicted mature peptide was characterized by HPLC and MS/MS sequencing. The amino acid sequence of livisin was confirmed as: GFLRGCWTKSFPPKPCL, with a disulfide bridge between Cys6 and Cys16, forming the typical inhibitory loop of a BBI. A comparative activity study between the native peptide and its inhibitory loop fragment found that both processed a similar inhibition efficacy against trypsin, consistent with the predefined activity motif. However, a modification by amidation of the Cterminus of both peptides increased their inhibition potency by 10-fold. Replacement and substitution of Lys9 by Phe, altered the proteolytic inhibitory activity of livisin to that of a chymotrypsin inhibitor. These data demonstrate that amphibian skin secretion is a remarkable source for discovery of novel protease inhibitors which can act as leads for potential drug discovery/development purposes.
|Number of pages||1|
|Publication status||Published - Aug 2016|
|Event||Drug Discovery & Therapy World Congress 2016 - Boston, United States|
Duration: 22 Aug 2016 → 25 Aug 2016
|Conference||Drug Discovery & Therapy World Congress 2016|
|Period||22/08/2016 → 25/08/2016|
- Amphibian skin secretion, molecular cloning, host defence, BBI, trypsin inhibitor.