Searching for new cell-penetrating agents: hybrid cyclobutane–proline γ,γ-peptides
作者:Esther Gorrea、Daniel Carbajo、Raquel Gutiérrez-Abad、Ona Illa、Vicenç Branchadell、Miriam Royo、Rosa M. Ortuño
DOI:10.1039/c2ob25220a
日期:——
Two generations of hybrid γ,γ-peptides containing cyclobutane amino acids and cis-γ-amino-L-proline joined in alternation have been synthesized and their capacity to cross the eukaryotic cell membrane has been evaluated. The first generation consists of di-, tetra- and hexapeptides, and their properties have been analyzed as well as the influence of peptide length and chirality of the cyclobutane residues. Results have shown that the absolute configuration of the cyclobutane amino acid does not have a relevant influence. The second generation consists of hybrid γ,γ-hexapeptides with a common backbone and distinct side chains introduced with different linkage types through the α-amino group (Nα) of the proline monomers. These peptides have been shown to be non-toxic towards HeLa cells and to internalize them effectively, the best results being obtained for the peptides with a spacer of five carbons between the Nα atom and the guanidinium group. The introduction of cyclobutane residues inside the sequence affords a good balance between charge and hydrophobicity, reducing the number of positive charges. This results in lower toxicity and similar cell-uptake properties when compared to previously described peptide agents.
已经合成了两代含有环丁烷氨基酸和顺式-γ-氨基-L-脯氨酸交替连接的杂合γ,γ-肽,并评估了它们穿过真核细胞膜的能力。第一代由二肽、四肽和六肽组成,分析了它们的性质以及肽长度和环丁烷残基手性的影响。结果表明环丁烷氨基酸的绝对构型没有相关影响。第二代由混合γ,γ-六肽组成,具有共同的主链和通过脯氨酸单体的α-氨基(Nα)引入不同连接类型的不同侧链。这些肽已被证明对 HeLa 细胞无毒,并能有效地内化它们,在 Nα 原子和胍基团之间具有五个碳间隔的肽获得最佳结果。在序列内部引入环丁烷残基可以在电荷和疏水性之间提供良好的平衡,从而减少正电荷的数量。与之前描述的肽制剂相比,这导致较低的毒性和相似的细胞摄取特性。