Rapidly growing antimicrobial resistance (AMR) against antibiotics has propelled the development of synthetic antimicrobial peptides (AMPs) as potential antimicrobial agents. An antimicrobial peptide Nle-Dab-Trp-Nle-Dab-Dab-Nle-CONH₂ (P36; Nle = norleucine, Dab = diaminobutyric acid, Trp = tryptophan) potent against Pseudomonas aeruginosa (P. aeruginosa) has been developed in the present study. Rational design strategy adopted in this study led to the improvisation of the therapeutic qualities such as activity, salt tolerance, cytotoxicity, and protease resistance of the template peptide P4, which was earlier reported from our group. P36 exhibited salt tolerant antimicrobial potency against P. aeruginosa, along with very low cytotoxicity against mammalian cell lines. P36 was found to be nonhemolytic and resistant toward protease degradation which qualified it as a potent antimicrobial agent. We have investigated the mechanism of action of this molecule in detail using several experimental techniques (spectroscopic, biophysical, and microscopic) and molecular dynamics simulations. P36 was a membrane active AMP with membrane destabilization and deformation abilities, leading to leakage of the intracellular materials and causing eventual cell death. The interaction between P36 and the microbial membrane/membrane mimics was primarily driven by electrostatics. P36 was unstructured in water and upon binding to the microbial membrane mimic SDS, suggesting no influence of secondary structure on its antimicrobial potency. Positive charge, optimum hydrophobic–hydrophilic balance, and chain length remained the most important concerns to be addressed while designing small cationic antimicrobial peptides.

中文翻译：

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描述蛋白酶抗性和耐盐合成抗菌肽对铜绿假单胞菌的作用机制

对抗生素的快速增长的抗菌素耐药性 (AMR) 推动了合成抗菌肽 (AMP) 作为潜在抗菌剂的发展。目前已开发出一种抗菌肽 Nle-Dab-Trp-Nle-Dab-Dab-Nle-CONH ₂ ( P36 ; Nle = 正亮氨酸, Dab = 二氨基丁酸, Trp = 色氨酸) 对铜绿假单胞菌( P. aeruginosa )有效学习。本研究中采用的合理设计策略导致模板肽P4的治疗质量（如活性、耐盐性、细胞毒性和蛋白酶抗性）的即兴发挥，这是我们小组较早报道的。P36表现出对铜绿假单胞菌的耐盐抗菌效力，以及对哺乳动物细胞系的极低细胞毒性。P36被发现是非溶血性的并且对蛋白酶降解具有抗性，这使其成为一种有效的抗微生物剂。我们使用几种实验技术（光谱、生物物理和微观）和分子动力学模拟详细研究了这种分子的作用机制。P36是一种膜活性 AMP，具有膜去稳定和变形能力，导致细胞内物质泄漏并最终导致细胞死亡。P36与微生物膜/膜模拟物之间的相互作用主要由静电驱动。P36在水中和与微生物膜模拟 SDS 结合后是非结构化的，表明二级结构对其抗菌效力没有影响。正电荷、最佳疏水-亲水平衡和链长仍然是设计小型阳离子抗菌肽时需要解决的最重要问题。