Frogs from the extensive amphibian family Hylidae are a rich source of peptides with therapeutic potential. Peptidomic analysis of norepinephrine-stimulated skin secretions from the Giant Gladiator Treefrog Boana boans (Hylidae: Hylinae) collected in Trinidad led to the isolation and structural characterization of five host-defense peptides with limited structural similarity to figainin 2 and picturin peptides from other frog species belonging to the genus Boana. In addition, the skin secretions contained high concentrations of tryptophyllin-BN (WRPFPFL) in both C-terminally α-amidated and non-amidated forms. Figainin 2BN (FLGVALKLGKVLG KALLPLASSLLHSQ) and picturin 1BN (GIFKDTLKKVVAAVLTTVADNIHPK) adopt α-helical conformations in trifluroethanol–water mixtures and in the presence of cell membrane models (sodium dodecylsulfate and dodecylphosphocholine micelles). The CD data also indicate contributions from turn structures. Both peptides and picturin 2BN (GLMDMLKKVGKVALT VAKSALLP) inhibited the growth of clinically relevant Gram-negative and Gram-positive bacteria with MIC values in the range 7.8–62.5 µM. Figainin 2BN was potently cytotoxic to A549, MDA-MB-231 and HT-29 human tumor-derived cells (LC50 = 7–14 µM) but displayed comparable potency against non-neoplastic HUVEC cells (LC50 = 15 µM) indicative of lack of selectivity for cancer cells.
Bibliographical noteFunding Information:
This work was partly supported by the Université de Rouen Normandie (URN), INSA Rouen Normandie, the Centre National de la Recherche Scientifique (CNRS), European Regional Development Fund (ERDF), Labex SynOrg (ANR-11-LABX-0029), Carnot Institute (I2C) and the Graduate School of Research XL-Chem (ANR-18-EURE-0020 XL CHEM). Support for this study was also provided by The UWI Campus Research and Publication (CR&P) Fund [CRP.3.NOV16.8(1)] and study and travel grant from The UWI for visiting Ulster University awarded to M.M.
© 2023 by the authors.
- antimicrobial peptide
- frog skin
- circular dichroism