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An Efficient Method for the Synthesis of Peptoids with Mixed Lysine-type/Arginine-type Monomers and Evaluation of Their Anti-leishmanial Activity
Published on: November 2, 2016
Conformation and lytic activity of eumenine mastoparan: a new antimicrobial peptide from wasp venom
M P dos Santos Cabrera1, B M de Souza, R Fontana
1Departmento de Física, Instituto de Biociências, Letras e Ciências Exatas, UNESP, São José do Rio Preto, SP 15054-000, Brazil.
Abstract:
Eumenine mastoparan-AF (EMP-AF) is a novel membrane active tetradecapeptide recently isolated from the venom of solitary wasp, Anterhynchium flavomarginatum micado. It was reported previously that EMP-AF peptide presented low cytolytic activities in human erythrocytes and in RBL-2H3 mast cells. In the present work, we observed that this peptide is able to permeate anionic liposomes, and in less extension also the neutral ones. We present evidences showing that the permeation ability is well correlated with the amount of helical conformation assumed by the peptides in these environments. This peptide also showed a broad-spectrum inhibitory activity against Gram-positive and Gram-negative bacteria. The permeability of liposomes and the antibiotic effect showed a significant reduction when C-terminus was deamidated (in acidic form). The removal of the three first amino acid residues from the N-terminus rendered the peptide inactive both in liposomes and in bacteria. The results suggest that the mechanism of action involves a threshold in the accumulation of the peptide at level of cell membrane.
Insights
Eumenine mastoparan-AF (EMP-AF), a wasp venom peptide, effectively permeates cell membranes and exhibits broad-spectrum antibacterial activity. Its helical structure and N-terminus are crucial for these functions.
Area of Science:
- Biochemistry
- Peptide Science
- Antimicrobial Research
Background:
- Eumenine mastoparan-AF (EMP-AF) is a novel tetradecapeptide from Anterhynchium flavomarginatum micado venom.
- Previous studies indicated low cytolytic activity in erythrocytes and mast cells.
Purpose of the Study:
- To investigate the membrane permeability and antibacterial properties of EMP-AF.
- To elucidate the structural basis for EMP-AF's activity.
Main Methods:
- Liposome permeation assays with anionic and neutral liposomes.
- Circular dichroism spectroscopy to assess helical conformation.
- Bacterial inhibition assays against Gram-positive and Gram-negative strains.
- Structure-activity relationship studies involving peptide modifications (deamidation, N-terminal truncation).
Main Results:
- EMP-AF effectively permeates anionic liposomes and, to a lesser extent, neutral liposomes.
- Peptide permeation correlates with helical conformation.
- EMP-AF displays broad-spectrum antibacterial activity.
- Deamidation of the C-terminus or removal of the N-terminal three amino acids significantly reduces liposome permeability and antibacterial efficacy.
Conclusions:
- EMP-AF's membrane activity and antibacterial effects are dependent on its helical structure and specific amino acid residues.
- The mechanism of action likely involves peptide accumulation to a threshold level at the cell membrane.
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