Browsing by Author "Alves, Eliane S. F."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Fast and potent bactericidal membrane lytic activity of PaDBS1R1, a novel cationic antimicrobial peptidePublication . Irazazabal, Luz N.; Porto, William F.; Fensterseifer, Isabel C. M.; Alves, Eliane S. F.; Matos, Carolina O.; Menezes, Antônio C. S.; Felício, Mário Romão; Abreu, Sónia Gonçalves; Santos, Nuno C.; Ribeiro, Suzana M.; Humblot, Vincent; Lião, Luciano M.; Ladram, Ali; Franco, Octavio L.Antimicrobial peptides (AMPs) are promising candidates for the development of future antibiotics. In an attempt to increase the efficacy of therapeutic AMPs, computer-based design methods appear as a reliable strategy. In this study, we evaluated the antimicrobial efficiency and mechanism of action of a novel designed AMP named PaDBS1R1, previously designed by means of the Joker algorithm, using a fragment of the ribosomal protein L39E from the archaeon Pyrobaculum aerophilum as a template. PaDBS1R1 displayed low micromolar broad-spectrum antimicrobial activity against Gram-negative (MIC of 1.5 μM) and Gram-positive (MIC of 3 μM) bacteria, including carbapenem-resistant Klebsiella pneumoniae (MIC of 6.25 μM) and methicillin-resistant Staphylococcus aureus (MIC of 12.5 μM), without cytotoxicity towards HEK-293 cells. In addition, membrane permeabilization and depolarization assays, combined with time-kill studies and FEG-SEM imaging, indicated a fast membrane permeation and further leakage of intracellular content. Biophysical studies with lipid vesicles show a preference of PaDBS1R1 for Gram-negative bacteria-like membranes. We investigated the three-dimensional structure of PaDBS1R1 by CD and NMR analyses. Our results suggest that PaDBS1R1 adopts an amphipathic α-helix upon interacting with hydrophobic environments, after an initial electrostatic interaction with negative charges, suggesting a membrane lytic effect. This study reveals that PaDBS1R1 has potential application in antibiotic therapy.
- Selective antibacterial activity of the cationic peptide PaDBS1R6 against Gram-negative bacteriaPublication . Fensterseifer, Isabel C. M.; Felício, Mário Romão; Alves, Eliane S. F.; Cardoso, Marlon H.; Torres, Marcelo D. T.; Matos, Carolina O.; Silva, Osmar N.; Lu, Timothy K.; Freire, Maurício V.; Neves, Natan C.; Gonçalves, Sónia; Lião, Luciano M.; Santos, Nuno C.; Porto, William F.; de la Fuente-Nunez, Cesar; Franco, Octavio L.Infections caused by Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa foremost among them, constitute a major worldwide health problem. Bioinformatics methodologies are being used to rationally design new antimicrobial peptides, a potential alternative for treating these infections. One of the algorithms used to develop antimicrobial peptides is the Joker, which was used to design the peptide PaDBS1R6. This study evaluates the antibacterial activities of PaDBS1R6 in vitro and in vivo, characterizes the peptide interaction to target membranes, and investigates the PaDBS1R6 structure in contact with mimetic vesicles. Moreover, we demonstrate that PaDBS1R6 exhibits selective antimicrobial activity against Gram-negative bacteria. In the presence of negatively charged and zwitterionic lipids the structural arrangement of PaDBS1R6 transits from random coil to α-helix, as characterized by circular dichroism. The tertiary structure of PaDBS1R6 was determined by NMR in zwitterionic dodecylphosphocholine (DPC) micelles. In conclusion, PaDBS1R6 is a candidate for the treatment of nosocomial infections caused by Gram-negative bacteria, as template for producing other antimicrobial agents.
- Structural studies of a lipid-binding peptide from tunicate hemocytes with anti-biofilm activityPublication . Silva, Osmar N.; Alves, Eliane S. F.; Fuente-Núñez, César de la; Ribeiro, Suzana M.; Mandal, Santi M.; Gaspar, Diana; Veiga, Ana S.; Castanho, Miguel A. R. B.; Andrade, Cesar A. S.; Nascimento, Jessica M.; Fensterseifer, Isabel C. M.; Porto, William F.; Correa, Jose R.; Hancock, Robert. E. W.; Korpole, Suresh Korpole; Oliveira, Aline L.; Liao, Luciano M.; Franco, Octavio L.Clavanins is a class of peptides (23aa) histidine-rich, free of post-translational modifications. Clavanins have been studied largely for their ability to disrupt bacterial membranes. In the present study, the interaction of clavanin A with membranes was assessed by dynamic light scattering, zeta potential and permeabilization assays. We observed through those assays that clavanin A lysis bacterial cells at concentrations corresponding to its MIC. Further, the structure and function of clavanin A was investigated. To better understand how clavanin interacted with bacteria, its NMR structure was elucidated. The solution state NMR structure of clavanin A in the presence of TFE-d3 indicated an α-helical conformation. Secondary structures, based on circular dichroism measurements in anionic sodium dodecyl sulfate (SDS) and TFE (2,2,2-trifluorethanol), in silico lipid-peptide docking and molecular simulations with lipids DPPC and DOPC revealed that clavanin A can adopt a variety of folds, possibly influencing its different functions. Microcalorimetry assays revealed that clavanin A was capable of discriminating between different lipids. Finally, clavanin A was found to eradicate bacterial biofilms representing a previously unrecognized function.