Carbohydrates are considered as promising templates for the display of multiple copies of antimicrobial peptides. Herein, we describe the design and synthesis of chimeric structures containing two or four copies of the antimicrobial peptides KKLFKKILKYL-NH2 (BP100) and KKLfKKILKYL-NH2 (BP143) attached to the carbohydrate template cyclodithioerythritol (cDTE) or α-D-galactopyranoside (Galp). The synthesis involved the preparation of the corresponding peptide aldehyde followed by coupling to an aminooxy-functionalized carbohydrate template. After purification, the multivalent display systems were obtained in high purities (90–98%) and in good yields (42–64%). These compounds were tested against plant and human pathogenic bacteria and screened for their cytotoxicity on eukaryotic cells. They showed lower MIC values than the parent peptides against the bacteria analyzed. In particular, the carbopeptides derived from cDTE and Galp, which contained two or four copies of BP100, respectively, were 2- to 8-fold more active than the monomeric peptide against the phytopathogenic bacteria. These results suggest that preassembling antimicrobial peptides to multimeric structures is not always associated with a significant improvement of the activity. In contrast, the carbopeptides synthesized were active against human red blood cells pointing out that peptide preassembly is critical for the hemolytic activity. Notably, peptide preassembly resulted in an enhanced bactericidal effect.
碳水化合物被认为是展示多重抗菌肽的有前景的模板。在这里,我们描述了含有两个或四个抗菌肽KKLFKKILKYL-NH2(BP100)和KKLfKKILKYL-NH2(BP143)的嵌合结构的设计和合成,这些肽与碳水化合物模板环二硫四醇(cDTE)或α-D-半乳糖苷(Galp)连接。合成涉及制备相应的肽醛,然后将其偶联到氨氧基功能化的碳水化合物模板上。经过纯化,多价展示系统以高纯度(90–98%)和良好收率(42–64%)获得。这些化合物被测试对植物和人类致病细菌的作用,并对真核细胞的细胞毒性进行筛选。它们显示出比分析的细菌的母体肽更低的最小抑菌浓度(MIC)值。特别是,从cDTE和Galp衍生的含有两个或四个BP100拷贝的碳肽,分别比单体肽对植物病原细菌活性高2到8倍。这些结果表明,将抗菌肽预装成多聚结构并不总是与活性显著改善有关。相反,合成的碳肽对人类红细胞具有活性,提示肽的预组装对溶血活性至关重要。值得注意的是,肽的预组装导致了增强的杀菌效果。