Membrane active peptides (MAPs) represent a class of short biomolecules that have shown great promise in facilitating intracellular delivery without disrupting cellular plasma membranes. Yet their clinical application has been stalled by numerous factors: off-target delivery, a requirement for high local concentration near cells of interest, degradation en route to the target site, and in the case of cell-penetrating peptides, eventual entrapment in endolysosomal compartments. The current method of deriving MAPs from naturally occurring proteins has restricted the discovery of new peptides that may overcome these limitations. Here, we describe a new branch of assays featuring high-throughput functional screening capable of discovering new peptides with tailored cell uptake and endosomal escape capabilities. The one-bead-one-compound (OBOC) combinatorial method is used to screen libraries containing millions of potential MAPs for binding to synthetic liposomes, which can be adapted to mimic various aspects of limiting membranes. By incorporating unnatural and d-amino acids in the library, in addition to varying buffer conditions and liposome compositions, we have identified several new highly potent MAPs that improve on current standards and introduce motifs that were previously unknown or considered unsuitable. Since small variations in pH and lipid composition can be controlled during screening, peptides discovered using this methodology could aid researchers building drug delivery platforms with unique requirements, such as targeted intracellular localization.

中文翻译：

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脂质体的组合文库筛选，用于发现膜活性肽。

膜活性肽（MAPs）代表了一类短的生物分子，它们在促进细胞内递送而不破坏细胞质膜方面显示出巨大的希望。然而，它们的临床应用受到许多因素的阻碍：脱靶递送，对感兴趣细胞附近局部高浓度的要求，在到达靶位点的过程中降解，以及在穿透细胞的肽的情况下，最终夹带在溶酶体区室中。从天然蛋白质衍生出MAP的当前方法限制了可以克服这些局限性的新肽的发现。在这里，我们描述了一个具有高通量功能筛选功能的检测新分支，该功能筛选能够发现具有定制细胞摄取和内体逃逸功能的新肽。单珠一化合物（OBOC）组合方法用于筛选包含数百万个可能与合成脂质体结合的潜在MAP的文库，该文库可用于模拟限制膜的各个方面。通过在库中掺入非天然和d-氨基酸，除了改变缓冲液条件和脂质体组成外，我们还发现了几种新的强效MAP，可改善当前标准并引入先前未知或认为不合适的基序。由于可以在筛选过程中控制pH和脂质成分的微小变化，因此使用这种方法发现的肽可以帮助研究人员构建具有独特要求（例如靶向细胞内定位）的药物递送平台。