Department of Chemistry, Brandeis University , Waltham, Massachusetts 02454, United States.
Department of Immunology, St. Jude Children's Research Hospital , Memphis, Tennessee 38105, United States.
J Am Chem Soc. 2018 Jan 31;140(4):1215-1218. doi: 10.1021/jacs.7b11582. Epub 2018 Jan 19.
Most of the reported mitochondria-targeting molecules are lipophilic and cationic, and thus they may become cytotoxic with accumulation. Here we show enzymatic cleavage of branched peptides that carry negative charges for targeting mitochondria. Conjugating a well-established protein tag (i.e., FLAG-tag) to self-assembling motifs affords the precursors that form micelles. Enzymatic cleavage of the hydrophilic FLAG motif (DDDDK) by enterokinase (ENTK) turns the micelles to nanofibers. After being taken up by cells, the micelles, upon the action of intracellular ENTK, turn into nanofibers to locate mainly at mitochondria. The micelles of the precursors are able to deliver cargos (either small molecules or proteins) into cells, largely to mitochondria and within 2 h. Preventing ENTK proteolysis diminishes mitochondria targeting. As the first report of using enzymatic self-assembly for targeting mitochondria and delivery cargos to mitochondria, this work illustrates a fundamentally new way to target subcellular organelles for biomedicine.
大多数报道的靶向线粒体的分子都是亲脂性和阳离子性的，因此它们可能会因积累而具有细胞毒性。在这里，我们展示了对带有负电荷的靶向线粒体的分支肽进行酶切。将成熟的蛋白质标签（即 FLAG 标签）连接到自组装基序上，可以得到形成胶束的前体。肠激酶（ENTK）对亲水性 FLAG 基序（DDDDK）的酶切作用将胶束转化为纳米纤维。进入细胞后，在细胞内 ENTK 的作用下，胶束转化为主要位于线粒体的纳米纤维。前体的胶束能够将 cargo（小分子或蛋白质）递送到细胞中，主要递送到线粒体中，并在 2 小时内完成。阻止 ENTK 蛋白水解会减少线粒体靶向。作为首次报道使用酶促自组装靶向线粒体并将 cargo 递送到线粒体的研究，这项工作为靶向细胞器用于生物医学提供了一种全新的方法。
