PDF(Pubmed)
Abstract：
Drug candidates that fail in clinical trials for efficacy reasons might still have favorable safety and bioavailability characteristics that could be exploited. A failed drug candidate could be repurposed if a receptor, such as an aptamer, were created that binds the compound with high specificity. Branaplam is a small molecule that was previously in development to treat spinal muscular atrophy and Huntington\'s disease. Here, we report the development of a small (48-nucleotide) RNA aptamer for branaplam with a dissociation constant of ∼150 nM. Starting with a combinatorial RNA pool integrating the secondary and tertiary structural scaffold of a Guanine-I riboswitch aptamer interspersed with regions of random sequence, in vitro selection yielded aptamer candidates for branaplam. Reselection and rational design were employed to improve binding of a representative branaplam aptamer candidate. A resulting variant retains the pseudoknot and two of the paired elements (P2 and P3) from the scaffold but lacks the enclosing paired element (P1) that is essential for the function of the natural Guanine-I riboswitch aptamer. A second combinatorial RNA pool based on the scaffold for TPP (thiamin pyrophosphate) riboswitches also yielded a candidate offering additional opportunities for branaplam aptamer development.
摘要：
由于功效原因在临床试验中失败的候选药物可能仍然具有可被利用的有利的安全性和生物利用度特征。如果受体，失败的候选药物可以被重新利用，例如适体，产生了以高特异性结合化合物。Branaplam是一种小分子，以前正在开发用于治疗脊髓性肌萎缩症和亨廷顿病。这里,我们报告了一个小的（48个核苷酸）RNA适体的发展与branaplam解离常数~150nM。从一个组合RNA库开始，整合了散布有随机序列区域的鸟嘌呤-I核糖开关适体的二级和三级结构支架，体外选择产生了branaplam的适体候选物。采用重新选择和合理设计来改善代表性branaplam适体候选物的结合。得到的变体保留了假结和来自支架的配对元件中的两个(P2和P3),但缺乏对于天然鸟嘌呤-I核糖开关适体的功能必需的封闭配对元件(P1)。基于TPP（焦磷酸硫胺素）核糖开关支架的第二个组合RNA池也产生了候选物，为branaplam适体开发提供了额外的机会。
