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

Abstract : A glycine-leucine-rich peptide was isolated from norepinephrine-stimulated skin secretions of the Sante Fe frog Leptodactylus laticeps (Leptodactylidae) whose primary structure (Gly-Leu-Val-Asn-Gly-Leu-Leu-Ser-Ser-Val-Leu-Gly-Gly-Gly-Gln-Gly-Gly-Gly-Gly-Leu-Leu-Gly-Gly-Ile-Leu) contains the (GXXXG)(3) motif found in the plasticins, previously identified only in phyllomedusid frogs (Hylidae). Circular dichroism studies showed that the secondary structure of the peptide, termed plasticin-L1, was markedly solvent-dependent displaying a random coil conformation in water, a beta-sheet structure in methanol, and an alpha-helical conformation in 50% trifluoroethanol-water. A synthetic replicate of the peptide did not inhibit the growth of Escherichia coli or Staphylococcus aureus or lyse human erythrocytes at concentrations up to 500 microM. At relatively high concentrations (>or=1 microM), the peptide produced a significant (P<0.05), although modest (139% of basal rate at 3 microM), increase in the rate of glucose-induced release of insulin from rat clonal BRIN-BD11 beta cells without increasing the rate of release of lactate dehydrogenase. A peptide, termed ocellatin-L2 was also identified in the skin secretion that was identical to the previously described ocellatin-L1 except for the substitution Asn(23)-->Asp. Ocellatin-L2 was devoid of antimicrobial and hemolytic activity but also showed significant activity in stimulating insulin release from BRIN-BD11 cells (181% of basal rate at 3 microM).
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https://hal-normandie-univ.archives-ouvertes.fr/hal-01960911
Contributor : Jérôme Leprince <>
Submitted on : Wednesday, December 19, 2018 - 4:05:00 PM
Last modification on : Tuesday, April 7, 2020 - 3:36:04 PM

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J Michael Conlon, Yasser Abdel-Wahab, Peter Flatt, Jérôme Leprince, Hubert Vaudry, et al.. A glycine-leucine-rich peptide structurally related to the plasticins from skin secretions of the frog Leptodactylus laticeps (Leptodactylidae). Peptides, Elsevier, 2009, 30 (5), pp.888-892. ⟨10.1016/j.peptides.2009.01.008⟩. ⟨hal-01960911⟩

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