Structural and mechanistic insights into EchAMP: A antimicrobial protein from the Echidna milk.
Antimicrobial proteins
EchAMP
Echidna
Intrinsically disordered protein
Milk
Monotremes
Journal
Biochimica et biophysica acta. Biomembranes
ISSN: 1879-2642
Titre abrégé: Biochim Biophys Acta Biomembr
Pays: Netherlands
ID NLM: 101731713
Informations de publication
Date de publication:
01 06 2019
01 06 2019
Historique:
received:
14
12
2018
revised:
27
03
2019
accepted:
28
03
2019
pubmed:
6
4
2019
medline:
15
2
2020
entrez:
6
4
2019
Statut:
ppublish
Résumé
Antibiotic resistance is a problem that necessitates the identification of new antimicrobial molecules. Milk is known to have molecules with antimicrobial properties (AMPs). Echidna Antimicrobial Protein (EchAMP) is one such lactation specific AMP exclusively found in the milk of Echidna, an egg-laying mammal geographically restricted to Australia and New Guinea. Previous studies established that EchAMP exhibits substantial bacteriostatic activity against multiple bacterial genera. However, the subsequent structural and functional studies were hindered due to the unavailability of pure protein. In this study, we expressed EchAMP protein using a heterologous expression system and successfully purified it to >95% homogeneity. The purified recombinant protein exhibits bacteriolytic activity against both Gram-positive and Gram-negative bacteria as confirmed by live-dead staining and scanning electron microscopy. Structurally, this AMP belongs to the family of intrinsically disordered proteins (IDPs) as deciphered by the circular-dichroism, tryptophan fluorescence, and NMR spectroscopy. Nonetheless, EchAMP has the propensity to acquire structure with amphipathic molecules, or membrane mimics like SDS, lipopolysaccharides, and liposomes as again observed through multiple spectroscopic techniques. Recombinant EchAMP exhibits broad-spectrum bacteriolytic activity by compromising the bacterial cell membrane integrity. Hence, we propose that this intrinsically disordered antimicrobial protein interact with the bacterial cell membrane and undergoes conformational changes to form channels in the membrane resulting in cell lysis. EchAMP, the evolutionarily conserved, lactation specific AMP from an oviparous mammal may find application as a broad-spectrum antimicrobial against pathogens that affect mammary gland or otherwise cause routine infections in humans and livestock.
Sections du résumé
BACKGROUND
Antibiotic resistance is a problem that necessitates the identification of new antimicrobial molecules. Milk is known to have molecules with antimicrobial properties (AMPs). Echidna Antimicrobial Protein (EchAMP) is one such lactation specific AMP exclusively found in the milk of Echidna, an egg-laying mammal geographically restricted to Australia and New Guinea. Previous studies established that EchAMP exhibits substantial bacteriostatic activity against multiple bacterial genera. However, the subsequent structural and functional studies were hindered due to the unavailability of pure protein.
RESULTS
In this study, we expressed EchAMP protein using a heterologous expression system and successfully purified it to >95% homogeneity. The purified recombinant protein exhibits bacteriolytic activity against both Gram-positive and Gram-negative bacteria as confirmed by live-dead staining and scanning electron microscopy. Structurally, this AMP belongs to the family of intrinsically disordered proteins (IDPs) as deciphered by the circular-dichroism, tryptophan fluorescence, and NMR spectroscopy. Nonetheless, EchAMP has the propensity to acquire structure with amphipathic molecules, or membrane mimics like SDS, lipopolysaccharides, and liposomes as again observed through multiple spectroscopic techniques.
CONCLUSIONS
Recombinant EchAMP exhibits broad-spectrum bacteriolytic activity by compromising the bacterial cell membrane integrity. Hence, we propose that this intrinsically disordered antimicrobial protein interact with the bacterial cell membrane and undergoes conformational changes to form channels in the membrane resulting in cell lysis.
GENERAL SIGNIFICANCE
EchAMP, the evolutionarily conserved, lactation specific AMP from an oviparous mammal may find application as a broad-spectrum antimicrobial against pathogens that affect mammary gland or otherwise cause routine infections in humans and livestock.
Identifiants
pubmed: 30951703
pii: S0005-2736(19)30078-1
doi: 10.1016/j.bbamem.2019.03.020
pii:
doi:
Substances chimiques
Anti-Bacterial Agents
0
Peptides
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
1260-1274Informations de copyright
Copyright © 2019 Elsevier B.V. All rights reserved.