The alyteserins: two families of antimicrobial peptides from the skin secretions of the midwife toad Alytes obstetricans (Alytidae).
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.
Conlon
J Michael
JM
Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, 17666 Al-Ain, United Arab Emirates. jmconlon@uaeu.ac.ae
Demandt
Anni
A
Nielsen
Per F
PF
Leprince
Jérôme
J
Vaudry
Hubert
H
Woodhams
Douglas C
DC
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001001:Anura; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012867:Skin / Q000737:chemistry / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013997:Time Factors
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D010446:Peptide Fragments; C573618:alyteserin-2a peptide, Alytes obstetricans