Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i>
The emergence of multidrug-resistant pathogens has driven the development of novel antimicrobial peptides (AMPs) as therapeutic alternatives. Lactolisterin LBU (LBU) is a bacteriocin with promising activity against Gram-positive bacteria, including <i>Staphylococcus aureus</i>. In this s...
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2025-07-01
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| author | Lazar Gardijan Milka Malešević Miroslav Dinić Aleksandar Pavić Nikola Plačkić Goran Jovanović Milan Kojić |
| author_facet | Lazar Gardijan Milka Malešević Miroslav Dinić Aleksandar Pavić Nikola Plačkić Goran Jovanović Milan Kojić |
| author_sort | Lazar Gardijan |
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| description | The emergence of multidrug-resistant pathogens has driven the development of novel antimicrobial peptides (AMPs) as therapeutic alternatives. Lactolisterin LBU (LBU) is a bacteriocin with promising activity against Gram-positive bacteria, including <i>Staphylococcus aureus</i>. In this study, we designed and evaluated a panel of amino acid variants of LBU to investigate domain–activity relationships and improve activity. Peptides were commercially synthesized, and their effect was evaluated for minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), hemolytic activity, cytotoxicity, in vivo toxicity, and virulence modulation. AlphaFold3 structural prediction of LBU revealed a four-helix topology with amphipathic and hydrophobic segments. Helical wheel projections identified helices I and IV as amphipathic, suggesting their potential involvement in membrane interaction and activity. Glycine-to-alanine substitutions at helix I markedly increased antimicrobial activity but altered toxicity profiles. In contrast, changes at helix junctions and kinks reduced antimicrobial activity. We also showed differential regulation of virulence genes upon sub-MIC treatment. Overall, rational substitution enabled identification of residues critical for activity and toxicity, providing insights into therapeutic tuning of lactolisterin-based peptides. |
| format | Article |
| id | doaj-art-b3fab3697a3f460b87387d595f4a4725 |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
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| spelling | doaj-art-b3fab3697a3f460b87387d595f4a47252025-08-20T04:00:53ZengMDPI AGMolecules1420-30492025-07-013015313410.3390/molecules30153134Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i>Lazar Gardijan0Milka Malešević1Miroslav Dinić2Aleksandar Pavić3Nikola Plačkić4Goran Jovanović5Milan Kojić6Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, SerbiaInstitute of Virology, Vaccines and Sera “Torlak”, 11000 Belgrade, SerbiaThe emergence of multidrug-resistant pathogens has driven the development of novel antimicrobial peptides (AMPs) as therapeutic alternatives. Lactolisterin LBU (LBU) is a bacteriocin with promising activity against Gram-positive bacteria, including <i>Staphylococcus aureus</i>. In this study, we designed and evaluated a panel of amino acid variants of LBU to investigate domain–activity relationships and improve activity. Peptides were commercially synthesized, and their effect was evaluated for minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), hemolytic activity, cytotoxicity, in vivo toxicity, and virulence modulation. AlphaFold3 structural prediction of LBU revealed a four-helix topology with amphipathic and hydrophobic segments. Helical wheel projections identified helices I and IV as amphipathic, suggesting their potential involvement in membrane interaction and activity. Glycine-to-alanine substitutions at helix I markedly increased antimicrobial activity but altered toxicity profiles. In contrast, changes at helix junctions and kinks reduced antimicrobial activity. We also showed differential regulation of virulence genes upon sub-MIC treatment. Overall, rational substitution enabled identification of residues critical for activity and toxicity, providing insights into therapeutic tuning of lactolisterin-based peptides.https://www.mdpi.com/1420-3049/30/15/3134lactolisterin LBUantimicrobial peptidebacteriocinamino acid substitution<i>Staphylococcus aureus</i>AlphaFold |
| spellingShingle | Lazar Gardijan Milka Malešević Miroslav Dinić Aleksandar Pavić Nikola Plačkić Goran Jovanović Milan Kojić Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> Molecules lactolisterin LBU antimicrobial peptide bacteriocin amino acid substitution <i>Staphylococcus aureus</i> AlphaFold |
| title | Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> |
| title_full | Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> |
| title_fullStr | Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> |
| title_full_unstemmed | Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> |
| title_short | Amino Acid Substitutions in Bacteriocin Lactolisterin BU Reveal Functional Domains Involved in Biological Activity Against <i>Staphylococcus aureus</i> |
| title_sort | amino acid substitutions in bacteriocin lactolisterin bu reveal functional domains involved in biological activity against i staphylococcus aureus i |
| topic | lactolisterin LBU antimicrobial peptide bacteriocin amino acid substitution <i>Staphylococcus aureus</i> AlphaFold |
| url | https://www.mdpi.com/1420-3049/30/15/3134 |
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