Gardijan Lazar, Malešević Milka, Dinić Miroslav, Pavić Aleksandar, Plačkić Nikola, Jovanović Goran, Kojić Milan
Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000 Belgrade, Serbia.
Institute of Virology, Vaccines and Sera "Torlak", 11000 Belgrade, Serbia.
Molecules. 2025 Jul 26;30(15):3134. doi: 10.3390/molecules30153134.
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 . 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.
多重耐药病原体的出现推动了新型抗菌肽（AMPs）作为治疗替代品的发展。乳李斯特菌素LBU（LBU）是一种对革兰氏阳性菌具有良好活性的细菌素，包括……。在本研究中，我们设计并评估了一组LBU的氨基酸变体，以研究结构域-活性关系并提高活性。肽段通过商业合成获得，并对其最小抑菌浓度（MIC）、最小杀菌浓度（MBC）、溶血活性、细胞毒性、体内毒性和毒力调节作用进行了评估。LBU的AlphaFold3结构预测显示其具有四螺旋拓扑结构，带有两亲性和疏水性片段。螺旋轮投影显示螺旋I和IV为两亲性，表明它们可能参与膜相互作用和活性。螺旋I上的甘氨酸到丙氨酸取代显著提高了抗菌活性，但改变了毒性特征。相比之下，螺旋连接处和扭结处的变化降低了抗菌活性。我们还表明，亚MIC处理后毒力基因存在差异调节。总体而言，合理的取代能够确定对活性和毒性至关重要的残基，为基于乳李斯特菌素的肽段的治疗性调整提供了见解。
