The alyteserins: Two families of antimicrobial peptides from the skin secretions of the midwife toad Alytes obstetricans (Alytidae)

J Michael Conlon (1) , Anni Demandt , Per Nielsen (2) , Jérôme Leprince (3, 4, 5) , Hubert Vaudry (3) , Douglas Woodhams , J. Michael Conlon , Per. Nielsen

1 Faculty of Medicine and Health Science
2 UCPH - University of Copenhagen = Københavns Universitet
3 Neuroendocrinologie cellulaire et moléculaire
4 DC2N - Différenciation et communication neuronale et neuroendocrine
5 DC2N - Différenciation et communication neuronale et neuroendocrine

Two families of structurally related C-terminally alpha-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH(2)) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH(2)) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu x NH(2)) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC=25 microM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC=50 microM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC(50)>100 microM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.

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

J Michael Conlon, Anni Demandt, Per Nielsen, Jérôme Leprince, Hubert Vaudry, et al.. The alyteserins: Two families of antimicrobial peptides from the skin secretions of the midwife toad Alytes obstetricans (Alytidae). Peptides, 2009, 30 (6), pp.1069-1073. ⟨10.1016/j.peptides.2009.03.004⟩. ⟨hal-01960916⟩