Synthesis, antibacterial activity and mode of action of novel linoleic acid–dipeptide–spermidine conjugates
作者:Seema Joshi、Rikeshwer P. Dewangan、Shruti Yadav、Diwan S. Rawat、Santosh Pasha
DOI:10.1039/c2ob26393a
日期:——
Towards therapeutically viable mimics of host defense cationic peptides (HDCPs) here we report the design and synthesis of a small library, based on a novel hydrophobicâdipeptideâspermidine template. Lipidated sequences 11, 14, 15, 16, 18 and 19 exhibited potent activity against susceptible as well as drug resistant Gram-positive and Gram-negative bacterial strains. Structureâactivity relationships of the template revealed a hydrophobicity window of 50â70% with minimum +2 charges to be crucial for activity and cell selectivity. Active sequences 14, 15 and 16 exhibited different modes of action based on dipeptide composition as revealed by studies on model membranes, intact bacterial cells and DNA. Further, severe damage to surface morphology of methicillin resistant S. aureus caused by 14, 15 and 16 at 10 Ã MIC was observed. The present study provides us two active sequences (14 and 16) with a membrane perturbing mode of action, cell selectivity to hRBCs and keratinocytes along with potent activity against clinically relevant pathogen MRSA. The designed template thus may prove to be a suitable probe to optimize sequences for better selectivity and potential to combat a wide range of drug resistant strains in further research.
针对治疗上可行的宿主防御阳离子肽 (HDCP) 模拟物,我们在此报告了基于新型疏水性二肽亚精胺模板的小型文库的设计和合成。脂化序列11、14、15、16、18和19对敏感以及耐药的革兰氏阳性和革兰氏阴性细菌菌株表现出有效的活性。模板的结构-活性关系揭示了 50-70% 的疏水性窗口,最小 +2 电荷对于活性和细胞选择性至关重要。对模型膜、完整细菌细胞和 DNA 的研究表明,活性序列 14、15 和 16 根据二肽组成表现出不同的作用模式。此外,观察到 14、15 和 16 在 10 × MIC 时对耐甲氧西林金黄色葡萄球菌的表面形态造成严重损害。本研究为我们提供了两种活性序列(14 和 16),它们具有膜扰动作用模式、对 hRBC 和角质形成细胞的细胞选择性以及针对临床相关病原体 MRSA 的有效活性。因此,设计的模板可能被证明是一种合适的探针,可以优化序列,以获得更好的选择性,并有可能在进一步的研究中对抗多种耐药菌株。