title: Selective amino acid substitution reduces cytotoxicity of the antimicrobial peptide mastoparan.
abstract: The emergence of antibiotic-resistant clinical isolates and the decreased rate of development of new antibiotics are a constant threat to human health. In this context, the therapeutic value of mastoparan (MP), a toxin from wasp venom, has been extensively studied. However, since MP shows significant cytotoxic activities, further optimization is needed. Here we evaluated the antimicrobial and cytolytic activities of an MP analog created by Ala-substitution in positions 5 and 8, named [I5, R8] mastoparan ([I5, R8] MP). We found that [I5, R8] MP displayed a broad-spectrum antimicrobial activity against bacteria and fungi (MIC in the range 3-25μM), without being hemolytic or cytotoxic toward HEK-293 cells. In addition, [I5, R8] MP-amide was highly potent (MIC=3μM) against antibiotic-resistant bacteria. The interaction with microbial membranes was investigated revealing that [I5, R8] MP is able to form an active amphipathic α-helix conformation and to disturb membranes causing lysis and cell death. Based on our findings, we hypothesize that [I5, R8] MP follows a mechanism of action similar to that proposed for MP, where the pore-forming activity leads to cell death. Our results indicate that hydrophobic moment modified by amino acid substitution may enhance MP selectivity.
authors.affiliation: Molecular Pathology Post-graduate Program, University of Brasília, Brasília, Distrito Federal, Brazil.
authors.forename: Luz N
authors.initials: LN
authors.lastname: Irazazabal
authors.affiliation: Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil.
authors.forename: William F
authors.initials: WF
authors.lastname: Porto
authors.affiliation: Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil; S-Inova Biotech, Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil.
authors.forename: Suzana M
authors.initials: SM
authors.lastname: Ribeiro
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (UPMC), CNRS, UMR 7197, Laboratoire de Réactivité de Surface (LRS), Paris, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Casale
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (UPMC), CNRS, UMR 7197, Laboratoire de Réactivité de Surface (LRS), Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Humblot
authors.affiliation: Sorbonne Universités, Université Pierre et Marie Curie (UPMC), CNRS, Institut de Biologie Paris-Seine (IBPS), Biogenèse des Signaux Peptidiques (BIOSIPE), Paris, France.
authors.forename: Ali
authors.initials: A
authors.lastname: Ladram
authors.affiliation: Molecular Pathology Post-graduate Program, University of Brasília, Brasília, Distrito Federal, Brazil; Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil; S-Inova Biotech, Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil. Electronic address: ocfranco@gmail.com.
authors.forename: Octavio L
authors.initials: OL
authors.lastname: Franco
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects / Q000254:growth & development; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D013293:Enterococcus faecalis / Q000187:drug effects / Q000254:growth & development; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D057809:HEK293 Cells; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D036341:Intercellular Signaling Peptides and Proteins; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000254:growth & development; D008087:Listeria / Q000187:drug effects / Q000254:growth & development; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D013045:Species Specificity; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000254:growth & development; D013329:Structure-Activity Relationship; D014862:Wasp Venoms / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014862:Wasp Venoms; C037500:mastoparan
keywords: Antimicrobial peptides; Hydrophobic moment; Mastoparan; Membrane permeabilization/depolarization; Rational design