Purification and characterization of antimicrobial peptides from the skin secretions of the carpenter frog Rana virgatipes (Ranidae, Aquarana)

J Michael Conlon (1) , Bency Abraham , Agnes Sonnevend , Thierry Jouenne (2) , Pascal Cosette (3) , Jérôme Leprince (4, 5, 6) , Hubert Vaudry (4) , Catherine Bevier , J. Michael Conlon

1 Faculty of Medicine and Health Science
2 PBM - Polymères, biopolymères, membranes
3 PBS - Polymères Biopolymères Surfaces
4 Neuroendocrinologie cellulaire et moléculaire
5 DC2N - Différenciation et communication neuronale et neuroendocrine
6 DC2N - Différenciation et communication neuronale et neuroendocrine

The members of the Aquarana (or Rana catesbeiana species group) form a well-supported monophyletic clade but phylogenetic relationships between species within the group are incompletely understood. Peptides that differentially inhibited the growth of bacteria were purified from electrically stimulated skin secretions of the carpenter frog Rana virgatipes. Structural characterization identified members of the ranatuerin-2 (3 peptides) and temporin (3-peptides) families, previously found in the skins of R. catesbeiana, R. clamitans, R. grylio and R. septentrionalis. Ranalexin, a peptide previously found only in the Aquarana, was isolated together with a variant (FFGLHNLVPSMLCVVRKKC) that lacks the propensity to adopt an alpha-helical conformation and so was devoid of antimicrobial activity. Two C-terminally alpha-amidated peptides belonging to the brevinin-2 family were isolated from the skin secretions that, like an ortholog from R. septentrionalis, lacked the C-terminal cyclic heptapeptide domain associated with members of this family. Ranatuerin-1, previously isolated from R. catesbeiana, R. clamitans and R. grylio but absent from R. septentrionalis, was also not identified in R. virgatipes. Synthetic replicates of temporin-1Va (FLSSIGKILGNLL.NH2), temporin-IVb (FLSIIAKVLGSLF.NH2) and temporin-1Vc (FLPLVTMLLGKLF.NH2) potently inhibited growth of Gram-positive bacteria (including methicillin-resistant Staphylococcus aureus). Temporin-1Va was also active against Gram-negative bacteria and the opportunistic yeast pathogen Candida albicans and had relatively weak hemolytic activity (LD50=120 microM) and may therefore represent a candidate for drug development. Our data support the placement of R. virgatipes in the Aquarana and indicate a closer phylogenetic relationship of R. virgatipes with R. septentrionalis than with R. catesbeiana, R. clamitans and R. grylio.

Domaines: Chimie thérapeutique; Interactions cellulaires [q-bio.CB]; Neurobiologie; Pharmacologie

J Michael Conlon, Bency Abraham, Agnes Sonnevend, Thierry Jouenne, Pascal Cosette, et al.. Purification and characterization of antimicrobial peptides from the skin secretions of the carpenter frog Rana virgatipes (Ranidae, Aquarana). Regulatory Peptides, 2005, 131 (1-3), pp.38-45. ⟨10.1016/j.regpep.2005.06.003⟩. ⟨hal-01960881⟩