Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India.
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Nucleic Acids Res. 2018 Jun 20;46(11):e65. doi: 10.1093/nar/gky185.
Pd-catalyzed C-C bond formation, an important vertebra in the spine of synthetic chemistry, is emerging as a valuable chemoselective transformation for post-synthetic functionalization of biomacromolecules. While methods are available for labeling protein and DNA, development of an analogous procedure to label RNA by cross-coupling reactions remains a major challenge. Herein, we describe a new Pd-mediated RNA oligonucleotide (ON) labeling method that involves post-transcriptional functionalization of iodouridine-labeled RNA transcripts by using Suzuki-Miyaura cross-coupling reaction. 5-Iodouridine triphosphate (IUTP) is efficiently incorporated into RNA ONs at one or more sites by T7 RNA polymerase. Further, using a catalytic system made of Pd(OAc)2 and 2-aminopyrimidine-4,6-diol (ADHP) or dimethylamino-substituted ADHP (DMADHP), we established a modular method to functionalize iodouridine-labeled RNA ONs in the presence of various boronic acid and ester substrates under very mild conditions (37°C and pH 8.5). This method is highly chemoselective, and offers direct access to RNA ONs labeled with commonly used fluorescent and affinity tags and new fluorogenic environment-sensitive nucleoside probes in a ligand-controlled stereoselective fashion. Taken together, this simple approach of generating functional RNA ON probes by Suzuki-Miyaura coupling will be a very important addition to the resources and tools available for analyzing RNA motifs.
钯催化的 C-C 键形成是合成化学脊柱中的重要环节，它作为生物大分子的后合成功能化的一种有价值的化学选择性转化方法正在出现。虽然已经有用于标记蛋白质和 DNA 的方法，但开发类似的通过交叉偶联反应标记 RNA 的方法仍然是一个主要挑战。在此，我们描述了一种新的钯介导的寡核苷酸（ON）标记方法，该方法涉及通过 Suzuki-Miyaura 交叉偶联反应对碘尿苷标记的 RNA 转录物进行转录后功能化。T7 RNA 聚合酶可有效地将 5-碘尿苷三磷酸（IUTP）掺入一个或多个位点的 RNA ON 中。此外，使用由 Pd(OAc)2 和 2-氨基嘧啶-4,6-二醇（ADHP）或二甲氨基取代的 ADHP（DMADHP）组成的催化体系，我们建立了一种模块化方法，可在非常温和的条件（37°C 和 pH 8.5）下，在各种硼酸和酯底物存在下对碘尿苷标记的 RNA ON 进行功能化。该方法具有高度的化学选择性，并可直接将常用的荧光和亲和标记物以及新的荧光环境敏感核苷探针标记到 RNA ON 上，以配体控制的立体选择性方式进行。总之，通过 Suzuki-Miyaura 偶联生成功能性 RNA ON 探针的这种简单方法将是分析 RNA 基序的现有资源和工具的重要补充。
