Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Teikyo University Institute of Medical Mycology, 359 Otsuka, Hachioji, Tokyo, 192-0395, Japan.
Nat Commun. 2020 Oct 1;11(1):4935. doi: 10.1038/s41467-020-18711-2.
Gramicidin A (1) is a peptide antibiotic that disrupts the transmembrane ion concentration gradient by forming an ion channel in a lipid bilayer. Although long used clinically, it is limited to topical application because of its strong hemolytic activity and mammalian cytotoxicity, likely arising from the common ion transport mechanism. Here we report an integrated high-throughput strategy for discovering analogues of 1 with altered biological activity profiles. The 4096 analogue structures are designed to maintain the charge-neutral, hydrophobic, and channel forming properties of 1. Synthesis of the analogues, tandem mass spectrometry sequencing, and 3 microscale screenings enable us to identify 10 representative analogues. Re-synthesis and detailed functional evaluations find that all 10 analogues share a similar ion channel function, but have different cytotoxic, hemolytic, and antibacterial activities. Our large-scale structure-activity relationship studies reveal the feasibility of developing analogues of 1 that selectively induce toxicity toward target organisms.
短杆菌肽 A（1）是一种肽类抗生素，通过在脂质双层中形成离子通道来破坏跨膜离子浓度梯度。尽管长期以来在临床上被广泛应用，但由于其强烈的溶血活性和哺乳动物细胞毒性，其应用仅限于局部应用，这可能是由于其共同的离子转运机制所致。在这里，我们报告了一种集成的高通量策略，用于发现具有改变的生物学活性谱的 1 的类似物。设计了 4096 个类似物结构以保持 1 的电荷中性、疏水性和通道形成特性。类似物的合成、串联质谱测序和 3 个微尺度筛选使我们能够鉴定出 10 个代表性的类似物。重新合成和详细的功能评估发现，这 10 个类似物都具有相似的离子通道功能，但具有不同的细胞毒性、溶血和抗菌活性。我们的大规模结构-活性关系研究揭示了开发选择性诱导靶生物体毒性的 1 的类似物的可行性。
