- MeSH
- Alamethicin pharmacology isolation & purification MeSH
- Endoplasmic Reticulum drug effects MeSH
- Erythrocyte Membrane drug effects MeSH
- Intracellular Membranes drug effects MeSH
- Mitochondria, Liver drug effects MeSH
- Rabbits MeSH
- Sarcoplasmic Reticulum drug effects MeSH
- Blood Platelets drug effects MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Animals MeSH
- MeSH
- Alamethicin diagnostic use MeSH
- Electrophoresis, Agar Gel methods utilization MeSH
- Lipid Bilayers analysis MeSH
- Publication type
- Congress MeSH
Alamethicin (ALM) is an antimicrobial peptide that is frequently employed in studies of the mechanism of action of pore-forming molecules. Advanced techniques of solid-state NMR spectroscopy (SSNMR) are important in these studies, as they are capable of describing the alignment of helical peptides, such as ALM, in lipid bilayers. Here, it is demonstrated how an analysis of the SSNMR measurements can benefit from fully periodic calculations, which employ the plane-wave density-functional theory (PW DFT) of the solid-phase geometry and related spectral parameters of ALM. The PW DFT calculations are used to obtain the structure of desolvated crystalline ALM and predict the NMR chemical shift tensors (CSTs) of its nuclei. A variation in the CSTs of the amidic nitrogens and carbonyl carbons along the ALM backbone is evaluated and included in simulations of the orientation-dependent anisotropic 15N and 13C chemical shift components. In this way, the influence of the site-specific structural effects on the experimentally determined orientation of ALM is shown in models of cell membranes.
- Publication type
- Journal Article MeSH
The increase in resistant bacterial strains necessitates the identification of new antimicrobial molecules. Antimicrobial peptides (AMPs) are an attractive option because of evidence that bacteria cannot easily develop resistance to AMPs. The peptaibols, a class of naturally occurring AMPs, have shown particular promise as antimicrobial drugs, but their development has been hindered by their mechanism of action not being clearly understood. To explore how peptaibols might interact with membranes, circular dichroism, vibrational circular dichroism, linear dichroism, Raman spectroscopy, Raman optical activity, neutron reflectivity and molecular dynamics simulations have been used to study a small library of peptaibol mimics, the Aib-rich peptides. All the peptides studied quickly partitioned and oriented in membranes, and we found evidence of chiral interactions between the phospholipids and membrane-embedded peptides. The protocols presented in this paper open new ground by showing how chiro-optical spectroscopies can throw light on the mechanism of action of AMPs.
- MeSH
- Circular Dichroism MeSH
- Phosphatidylcholines chemistry MeSH
- Antimicrobial Cationic Peptides chemistry metabolism MeSH
- Lipid Bilayers chemistry metabolism MeSH
- Peptaibols chemistry metabolism MeSH
- Molecular Dynamics Simulation * MeSH
- Stereoisomerism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Current antibiotics and chemotherapeutics are becoming ineffective because pathogenic bacteria and tumor cells have developed multiple drug resistance. Therefore, it is necessary to find new substances that can be used in treatment, either alone or as sensitizing molecules in combination with existing drugs. Peptaibols are bioactive, membrane-active peptides of non-ribosomal origin, mainly produced by filamentous fungi such as Trichoderma spp. This study focused on producing peptaibol-rich extracts from Trichoderma atroviride O1, cultivated on malt extract agar (MA) under circadian and constant darkness conditions for 13 days. Peptaibol production was detected by MALDI-TOF mass spectrometry after six days of cultivation. The extracts demonstrated antibacterial activity against Staphylococcus aureus strains, particularly the methicillin-resistant variant, but not against the Gram-negative Pseudomonas aeruginosa. Quorum sensing interference revealed that a peptaibol-rich extract suppressed Vibrio campbellii BAA-1119's AI-2 signaling system to a degree comparable with gentamycin. Beyond antibacterial properties, the extracts exhibited notable antiproliferative activity against human ovarian cancer cells and their adriamycin-resistant subline in both 2D and 3D models. Specifically, MA-derived extracts reduced ovarian cancer cell viability by 70% at 50 μg/mL, especially under light/dark regime of cultivation. Compared to previously published results for PDA-based extracts, MA cultivation shifted the biological effects of peptaibol-containing extracts toward anticancer potential. These findings support the idea that modifying fungal cultivation parameters, the bioactivity of secondary metabolite mixtures can be tailored for specific therapeutic applications.
- MeSH
- Agar * chemistry MeSH
- Anti-Bacterial Agents * pharmacology metabolism MeSH
- Hypocreales MeSH
- Culture Media chemistry MeSH
- Humans MeSH
- Microbial Sensitivity Tests MeSH
- Cell Line, Tumor MeSH
- Peptaibols * pharmacology metabolism biosynthesis chemistry MeSH
- Cell Proliferation drug effects MeSH
- Antineoplastic Agents * pharmacology metabolism MeSH
- Pseudomonas aeruginosa drug effects MeSH
- Staphylococcus aureus drug effects MeSH
- Trichoderma * metabolism growth & development chemistry MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Fighting resistance to antibiotics and chemotherapeutics has brought bioactive peptides to the fore. Peptaibols are short α-aminoisobutyric acid-containing peptides produced by Trichoderma species. Here, we studied the production of peptaibols by Trichoderma atroviride O1 and evaluated their antibacterial and anticancer activity against drug-sensitive and multidrug-resistant bacterium and cancer cell lines. This was substantiated by an analysis of the activity of the peptaibol synthetase-encoding gene. Atroviridins, 20-residue peptaibols were detected using MALDI-TOF mass spectrometry. Gram-positive bacteria were susceptible to peptaibol-containing extracts of T. atroviride O1. A synergic effect of extract constituents was possible, and the biolo-gical activity of extracts was pronounced in/after the peak of peptaibol synthetase activity. The growth of methicillin-resistant Staphylococcus aureus was reduced to just under 10% compared to the control. The effect of peptaibol-containing extracts was strongly modulated by the lipoteichoic acid and only slightly by the horse blood serum present in the cultivation medium. Peptaibol-containing extracts affected the proliferation of human breast cancer and human ovarian cancer cell lines in a 2D model, including the multidrug-resistant sublines. The peptaibols influenced the size and compactness of the cell lines in a 3D model. Our findings indicate the molecular basis of peptaibol production in T. atroviride O1 and the potential of its peptaibol-containing extracts as antimicrobial/anticancer agents.
- MeSH
- Anti-Bacterial Agents pharmacology MeSH
- Drug Resistance, Bacterial * MeSH
- Fungal Proteins metabolism MeSH
- Hypocreales enzymology metabolism MeSH
- Horses MeSH
- Humans MeSH
- Ligases metabolism MeSH
- Methicillin-Resistant Staphylococcus aureus drug effects MeSH
- MCF-7 Cells MeSH
- Cell Line, Tumor MeSH
- Neoplasms drug therapy MeSH
- Peptaibols analysis metabolism pharmacology MeSH
- Antineoplastic Agents pharmacology MeSH
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
