Fast and potent bactericidal membrane lytic activity of PaDBS1R1, a novel cationic antimicrobial peptide

• Published in: Biochimica et biophysica acta. Biomembranes Vol. 1861; no. 1; pp. 178 - 190
• Main Authors: Irazazabal, Luz N., Porto, William F., Fensterseifer, Isabel C.M., Alves, Eliane S.F., Matos, Carolina O., Menezes, Antônio C.S., Felício, Mário R., Gonçalves, Sónia, Santos, Nuno C., Ribeiro, Suzana M., Humblot, Vincent, Lião, Luciano M., Ladram, Ali, Franco, Octavio L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-01-2019; Elsevier
• Subjects: Antimicrobial peptides; Chemical Sciences; Circular dichroism (CD); Electron microscopy (EM); Medicinal Chemistry; Membrane permeabilization/depolarization; Nuclear magnetic resonance (NMR); Rational design; THP-1; CD; MIC; FEG-SEM; Membrane permeabilization/depolarization; Circular dichroism (CD); AMPs; Electron microscopy (EM); NMR; Rational design; Antimicrobial peptides; HEK-293; Nuclear magnetic resonance (NMR)
• ISSN: 0005-2736; 1879-2642
• DOI: 10.1016/j.bbamem.2018.08.001

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.
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•PaDBS1R1 has a broad spectrum of antimicrobial activity.•PaDBS1R1 kills bacteria within 5 min.•PaDBS1R1 adopts an α-helix structure on hydrophobic environments.