A glycine-leucine-rich peptide structurally related to the plasticins from skin secretions of the frog Leptodactylus laticeps (Leptodactylidae)

Structural diversity and species distribution of host-defense peptides in frog skin secretions

“…More recently, glycine-leucine-rich peptides have been isolated from skin secretions of L. laticeps [68] and L. pentadactylus [69] that show limited structural similarity to the plasticins, previously identified only in phyllomedusid frogs of the family Hylidae. Like the plasticins, the peptide from L. laticeps adopts a random coil conformation in water, a b-sheet structure in methanol, and an alphahelical conformation in 50% trifluoroethanol-water.…”

“…Like the plasticins, the peptide from L. laticeps adopts a random coil conformation in water, a b-sheet structure in methanol, and an alphahelical conformation in 50% trifluoroethanol-water. This component lacked antimicrobial activity [68], but the peptide from L. pentadactylus, unexpectedly in view of its low cationicity, was active against Gram-negative bacteria [69].…”

Antimicrobial Peptides: New Frontiers in the Therapy of Infections

“…Plasticin-L1, more recently isolated from the South American frog Leptodactylus laticeps, falls into the second category and is devoid of cytolytic activity against Gram-positive and Gram-negative bacteria. However, in contrast to the other plasticins, it does not produce lysis of human erythrocytes at concentrations up to 500 M (Conlon et al, 2009). The plasticin peptide family constitutes a good model to address the relationships between structural polymorphism, membrane-interacting property, and biological activity of antimicrobial, cell-penetrating, and viral fusion peptides (El Amri & Nicolas, 2008).…”

“…They are quite similar as far as amino acid sequence, hydrophobicity, and amphipathicity are concerned, but differ markedly in their conformational plasticity and spectrum of activity (Vanhoye et al, 2003). The plasticins from phyllomedusid frogs of the Hylidae family may be divided into two classes on the basis of their cytolytic activities: the strongly cationic peptides plasticin-B1 (from P. bicolor) and -S1 (from P. sauvagei) that contain lysine residues and show potent, broad spectrum antimicrobial activity and hemolytic activity; and the weakly cationic or neutral plasticins (plasticin-A1, from Agalychnis annae, plasticin -C1 and -C2 from A. callidryas, and plasticin-DA1 from Pachymedusa danicolor), that are hemolytic but devoid of antibacterial activity (Conlon et al, 2009). Plasticin-L1, more recently isolated from the South American frog Leptodactylus laticeps, falls into the second category and is devoid of cytolytic activity against Gram-positive and Gram-negative bacteria.…”

Antimicrobial peptides from amphibians

“…The study also showed that these structures are crucial for its biology activity (100). Ocellatin L2 and plasticin-L1 are devoid of antimicrobial activity but both have the ability to release insulin from BRIN-BD11 cells (101). Pseudin-2 isolated from the skin of the paradoxical frog Pseudis paradoxa is a cationic and a-helical peptide that can stimulate insulin release from the BRIN-BD11 clonal b cell line without hemolytic activity (102).…”