Biomolecules do not fold into a single 3D structure but rather form dynamic ensembles of many inter-converting conformations. Knowledge of dynamic ensembles is key for understanding how biomolecules fold and function, and for rationally manipulating their activities in drug discovery and synthetic biology. However, solving dynamic ensembles of biomolecules at atomic resolution is a major challenge in structural biology because the information required to specify the position of all atoms in thousands of conformations in an ensemble far exceeds the information content of experimental measurements. Here we addressed the data gap and dramatically simplified and accelerated RNA ensemble determination by using structure prediction tools that leverage the growing database of RNA structures to generate a conformational library. Library refinement with NMR residual dipolar couplings enabled determination of an atomic-resolution ensemble for HIV-1 TAR as confirmed by quantum-mechanical calculations of NMR chemical shifts, comparison to a crystal structure of a substate, and through the successful redistribution of the ensemble by design using atomic mutagenesis. The ensemble provides an unprecedented view of how bulge residues cooperatively flip out and undergo sugar repuckering to allow the adjoining helices to stack. The generality of this approach will make determination of atomic-resolution RNA ensembles routine.

中文翻译：

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原子分辨率的RNA动态集合

生物分子不会折叠成单个3D结构，而是形成许多相互转换构象的动态集合体。动态合奏的知识对于理解生物分子如何折叠和起作用，以及合理地操纵其在药物发现和合成生物学中的活动至关重要。但是，以原子分辨率求解生物分子的动态集合是结构生物学中的一项重大挑战，因为指定集合中成千上万个构象中所有原子的位置所需的信息远远超过了实验测量的信息内容。在这里，我们利用结构预测工具解决了数据缺口，并显着简化和加速了RNA集成测定，该工具利用了不断增长的RNA结构数据库来生成构象文库。通过NMR残留偶极偶合的文库改进，可以确定HIV-1 TAR的原子分辨率整体，这已通过NMR化学位移的量子力学计算，与亚态的晶体结构比较以及通过成功地重新分布整体而得以确认使用原子诱变进行设计。该合奏提供了一个前所未有的视图，可以看到凸出的残留物如何协作地倒出并经历重新吸食糖以使相邻的螺旋堆积。这种方法的普遍性将使确定原子分辨率的RNA序列成为常规方法。并通过使用原子诱变的设计成功地重新集成了乐团。该合奏提供了一个前所未有的视图，可以看到凸出的残留物如何协作地倒出并经历重新吸食糖以使相邻的螺旋堆积。这种方法的普遍性将使确定原子分辨率的RNA序列成为常规方法。并通过使用原子诱变的设计成功地重新集成了乐团。该合奏提供了一个前所未有的视图，可以看到凸出的残留物如何协作地倒出并经历重新吸食糖以使相邻的螺旋堆积。这种方法的普遍性将使确定原子分辨率的RNA序列成为常规方法。