Quinone methide precursors 2 and 3 were protected with a photoreactive 2-nitrobenzyl group and conjugated to peptide nucleic acids (PNA) using a Huisgen click reaction. After brief irradiation at 365 nm, cross-linking with complementary RNA strands started and was analyzed with an ALFexpress sequencer. When this method was used, the gel temperature had a major influence on apparent rates. Quinone methides are known to form transient as well as stable bonds with nucleotides. Although both were detected at 25 °C, analysis at 57 °C only recorded the stable types of cross-links, suggesting much slower alkylation kinetics. Linker 11 allowed us to attach quinone methides to internal positions of the PNA/RNA duplex and to capture a model of miR-20a with good efficiency.

中文翻译：

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光照活化后，甲基醌醌前体烷基核糖核酸的肽核酸缀合物。

用光反应性2-硝基苄基保护醌甲基化物前体2和3，并使用Huisgen点击反应将其与肽核酸（PNA）缀合。在365 nm处短暂照射后，开始与互补RNA链进行交联，并使用ALFexpress测序仪进行分析。当使用该方法时，凝胶温度对表观速率有重大影响。已知醌甲基化物与核苷酸形成瞬时以及稳定的键。尽管两者均在25°C下检测到，但在57°C下的分析仅记录了稳定类型的交联，表明烷基化动力学要慢得多。接头11允许我们将醌甲基化物连接到PNA / RNA双链体的内部位置，并以良好的效率捕获miR-20a模型。