Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA.
Nat Chem. 2018 Apr;10(4):420-427. doi: 10.1038/s41557-018-0008-9. Epub 2018 Mar 5.
The evolution of sequence-defined synthetic polymers made of building blocks beyond those compatible with polymerase enzymes or the ribosome has the potential to generate new classes of receptors, catalysts and materials. Here we describe a ligase-mediated DNA-templated polymerization and in vitro selection system to evolve highly functionalized nucleic acid polymers (HFNAPs) made from 32 building blocks that contain eight chemically diverse side chains on a DNA backbone. Through iterated cycles of polymer translation, selection and reverse translation, we discovered HFNAPs that bind proprotein convertase subtilisin/kexin type 9 (PCSK9) and interleukin-6, two protein targets implicated in human diseases. Mutation and reselection of an active PCSK9-binding polymer yielded evolved polymers with high affinity (K = 3 nM). This evolved polymer potently inhibited the binding between PCSK9 and the low-density lipoprotein receptor. Structure-activity relationship studies revealed that specific side chains at defined positions in the polymers are required for binding to their respective targets. Our findings expand the chemical space of evolvable polymers to include densely functionalized nucleic acids with diverse, researcher-defined chemical repertoires.
由聚合酶或核糖体相容的砌块以外的构建块合成的序列定义的聚合物的进化，具有产生新型受体、催化剂和材料的潜力。在这里，我们描述了一种连接酶介导的 DNA 模板聚合和体外选择系统，用于进化由 32 个砌块组成的高度官能化的核酸聚合物 (HFNAPs)，这些砌块在 DNA 主链上具有八个化学上不同的侧链。通过聚合物翻译、选择和反向翻译的迭代循环，我们发现了与两种蛋白质靶标（参与人类疾病的蛋白转化酶枯草溶菌素/激肽释放酶 9 (PCSK9) 和白细胞介素 6）结合的 HFNAPs。对活性 PCSK9 结合聚合物进行突变和重新选择，得到了具有高亲和力 (K = 3 nM) 的进化聚合物。这种进化聚合物可有效抑制 PCSK9 与低密度脂蛋白受体之间的结合。结构-活性关系研究表明，聚合物中特定位置的特定侧链是与各自靶标结合所必需的。我们的研究结果将可进化聚合物的化学空间扩展到包含具有各种研究人员定义的化学库的密集官能化核酸。
