Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.
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http://dx.doi.org/10.1038/srep01854 | DOI Listing |
Eur J Pharm Sci
January 2025
Nanotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Pharmaceutical Nanotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran. Electronic address:
Premature drug release is the primary hindrance to the effective function of the lyso-thermosensitive liposomes (LTSLs) of doxorubicin (Dox), known as ThermoDox® for the treatment of cancer. Herein, we have optimized LTSLs by using a combination of phospholipids (PLs) with high transition temperatures (Tm) to improve the therapeutic outcome in an assisted ultrasound approach. For this, several Dox LTSLs were prepared using the remote loading method at varying molar ratios (0 to 90%) of DPPC (Tm 41°C) and HSPC (Tm 54.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Research Institute for Systems Biology and Medicine (RISBM), Nauchnyi proezd 18, 117246 Moscow, Russia.
SARS-CoV-2 viral entry requires membrane fusion, which is facilitated by the fusion peptides within its spike protein. These predominantly hydrophobic peptides insert into target membranes; however, their precise mechanistic role in membrane fusion remains incompletely understood. Here, we investigate how FP1 (SFIEDLLFNKVTLADAGFIK), the N-terminal fusion peptide, modulates membrane stability and barrier function across various model membrane systems.
View Article and Find Full Text PDFBiomolecules
December 2024
Drug Chemistry and Technology Department, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy.
essential oil is a natural substance able to inhibit the growth of several pathogens. This antimicrobial effect is often attributed to its ability to penetrate cellular structures and disrupt them. Although these properties are recognized as playing a key role in the mechanism of action of this substance, many unresolved issues still exist, and fundamental studies focused on such aspects are scarce.
View Article and Find Full Text PDFAntibiotics (Basel)
January 2025
Departamento de Química, Faculdade de Ciências Exatas, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Campus JK, Diamantina 39100-000, MG, Brazil.
This study investigates the structural and biophysical properties of the wild-type antimicrobial peptide LyeTx I, isolated from the venom of the spider , and its analog LyeTx I-b, designed to enhance antibacterial activity, selectivity, and membrane interactions by the acetylation and increased amphipathicty. : To understand the mechanisms behind these enhanced properties, comparative analyses of the structural, topological, biophysical, and thermodynamic aspects of the interactions between each peptide and phospholipid bilayers were evaluated. Both peptides were isotopically labeled with H-Ala and N-Leu to facilitate structural studies via NMR spectroscopy.
View Article and Find Full Text PDFAntioxidants (Basel)
January 2025
Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy.
Investigating amyloid-β (Aβ) peptides in solution is essential during the initial stages of developing lead compounds that can influence Aβ fibrillation while the peptide is still in a soluble state. The tendency of the Aβ(1-42) peptide to misfold in solution, correlated to the aetiology of Alzheimer's disease (AD), is one of the main hindrances to characterising its aggregation kinetics in a cell-mimetic environment. Moreover, the Aβ(1-42) aggregation triggers the unfolded protein response (UPR) in the endoplasmic reticulum (ER), leading to cellular dysfunction and multiple cell death modalities, exacerbated by reactive oxygen species (ROS), which damage cellular components and trigger inflammation.
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