Temporins, Antimicrobial Peptides from the European Red Frog Rana temporaria

Abstract

A cDNA,library from the skin of Kuna temporaria has been screened using a cDNA fragment probe that encodes the signal peptide of the precursor of esculentin from the skin secretion of Rana esculentu. With this approach, the cDNAs encoding the precursors of three peptides were isolated. Subsequently, the peptides predicted from the sequence of the cloned cDNAs as well as several structurally related peptides could be isolated from the skin secretion of R. temporuria. These peptides, which were named temporins, have a length of 10-13 residues and show some sequence similarity to hemolytic peptides Natural and synthetic temporins have antibacterial activity against gram-positive bacteria, but they are not hemolytic. Temporins are the smallest antibacterial peptides hitherto found in nature.

A Synergism between Temporins toward Gram-negative Bacteria Overcomes Resistance Imposed by the Lipopolysaccharide Protective Layer

“…Therefore, before reaching the cytoplasmic membrane, the peptides need to interact and traverse both the LPS and the peptidoglycan layers (66,67). The outer cell envelope was previously considered to be a barrier against temporins, because E. coli strains with the progressively decreased LPS-polysaccharide chain were found to be concomitantly more sensitive to these peptides (30,68). Here, we provide an explanation for the inactivity of temporins A and B toward Gram-negative bacteria.…”

“…Other examples of families of AMPs with high structural similarities include cecropins from insects (31,32), the mammalian defensins and cathelicidins, isolated from circulating leukocytes and epithelia (33,34), and the human salivary histatins (35). In Amphibia, temporins represent the largest family of AMPs (more than 40 members), and up to 10 isoforms have been identified in a single specimen (30). They are among the smallest amphipathic ␣-helical AMPs found in nature to date (10 to 14 amino acids), containing only a few positively charged amino acids (the net charge at a neutral pH ranging from 0 to ϩ3) and are active particularly toward Gram-positive bacteria.…”

“…These families encompass bombinins and bombinins H, from the European toads Bombina variegata and Bombina orientalis (20 -23), magainins from the African clawed frog Xenopus laevis (24), dermaseptins from the South American arboreal frog Phyllomedusa sauvagii (25,26), and those from the Rana genus (e.g. brevinins, ranalexins, esculentins, and temporins) (19,(27)(28)(29)(30). Other examples of families of AMPs with high structural similarities include cecropins from insects (31,32), the mammalian defensins and cathelicidins, isolated from circulating leukocytes and epithelia (33,34), and the human salivary histatins (35).…”

Antimicrobial peptides from amphibians

“…Temporins, which comprise between 10 and 14 amino acid residues, were firstly identified in the skin of the European frog Rana esculenta (18) and then Rana temporaria (2). Recently, an AMP (odorranain V) containing only 9 amino acid residues was identified from the frog O. grahami (24).…”

“…In the past decades, several bioactive agents including antimicrobial peptides (AMPs), pharmacological peptides or peptides with unknown function have been identified from skin secretions of amphibians (1)(2)(3). These agents are important to prevent attack from aggressors (4,5).…”