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Background: The peptide VLL-28, identified in the sequence of an archaeal protein, the transcription factor Stf76 from Sulfolobus islandicus, was previously identified and characterized as an antimicrobial peptide, possessing a broad-spectrum antibacterial activity.
Methods: Through a combined approach of NMR and Circular Dichroism spectroscopy, Dynamic Light Scattering, confocal microscopy and cell viability assays, the interaction of VLL-28 with the membranes of both parental and malignant cell lines has been characterized and peptide mechanism of action has been studied.
Results: It is here demonstrated that VLL-28 selectively exerts cytotoxic activity against murine and human tumor cells. By means of structural methodologies, VLL-28 interaction with the membranes has been proven and the binding residues have been identified. Confocal microscopy data show that VLL-28 is internalized only into tumor cells. Finally, it is shown that cell death is mainly caused by a time-dependent activation of apoptotic pathways.
Conclusions: VLL-28, deriving from the archaeal kingdom, is here found to be endowed with selective cytotoxic activity towards both murine and human cancer cells and consequently can be classified as an ACP.
General Significance: VLL-28 represents the first ACP identified in an archaeal microorganism, exerting a trans-kingdom activity.
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http://dx.doi.org/10.1016/j.bbagen.2017.06.009 | DOI Listing |
ChemMedChem
September 2025
Faculty of Pharmacy, PHENIKAA University, Hanoi, 12116, Vietnam.
Antimicrobial peptides (AMPs) have emerged as promising candidates for combating drug-resistant pathogens and certain cancer types. However, their therapeutic applications are often limited by undesired hemolytic activity, while many AMPs exhibit only moderate potency. Herein, the "helical wheel rotation" strategy as a simple, cost-effective, and modular approach to optimize the pharmacological properties of amphipathic α-helical AMPs without altering their amino acid composition is explored.
View Article and Find Full Text PDFMicrobiol Spectr
September 2025
Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon.
In Gram-negative bacteria, resistance-nodulation-division (RND)-type efflux pumps, particularly AcrAB-TolC, play a critical role in mediating resistance to antimicrobial agents and toxic metabolites, contributing to multidrug resistance. is an entomopathogenic bacterium that has garnered significant interest due to its production of bioactive specialized metabolites with anti-inflammatory, antimicrobial, and scavenger deterrent properties. In previous work, we demonstrated that AcrAB confers self-resistance to stilbenes in TT01.
View Article and Find Full Text PDFJ Ind Microbiol Biotechnol
September 2025
Department of Biochemistry University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Glycocins are a growing family of ribosomally synthesized and posttranslationally modified peptides (RiPPs) that are O- and/or S-glycosylated. Using a sequence similarity network of putative glycosyltransferases, the thg biosynthetic gene cluster was identified in the genome of Thermoanaerobacterium thermosaccharolyticum. Heterologous expression in Escherichia coli showed that the glycosyltransferase (ThgS) encoded in the biosynthetic gene cluster (BGC) adds N-acetyl-glucosamine (GlcNAc) to Ser and Cys residues of ThgA.
View Article and Find Full Text PDFMicrobiol Spectr
September 2025
USDA, Agricultural Research Service, Southern Regional Research Center, New Orleans, Louisiana, USA.
With increasing antibiotic resistance and the paucity of new antibiotics in the development pipeline, exploration of antimicrobial peptide applications alone or in combination with existing antibiotics is more crucial than ever. The recent study by J. Varin-Simon, E.
View Article and Find Full Text PDFJ Appl Microbiol
September 2025
Sivas Cumhuriyet University, Faculty of Medicine, Department of Medical Microbiology, 58140 Sivas, Türkiye.
Aims: The increasing antimicrobial resistance, particularly in Acinetobacter baumannii, complicates the treatment of infections, leading to higher morbidity, mortality, and economic costs. Herein, we aimed to determine the in vitro antimicrobial, synergistic, and antibiofilm activities of colistin (COL), meropenem, and ciprofloxacin antibiotics, and curcumin, punicalagin, geraniol (GER), and linalool (LIN) plant-active ingredients alone and in combination against 31 multidrug-resistant (MDR) A. baumannii clinical isolates.
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