Institute of Biophysics and Physical Biochemistry, Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
Department of Informatics, TU Munich, Garching, Germany.
Nat Chem Biol. 2022 Oct;18(10):1152-1160. doi: 10.1038/s41589-022-01111-6. Epub 2022 Aug 25.
Nuclear magnetic resonance (NMR) methods that quantitatively probe motions on molecular and atomic levels have propelled the understanding of biomolecular processes for which static structures cannot provide a satisfactory description. In this work, we studied the structure and dynamics of the essential 100-kDa eukaryotic 5'→3' exoribonuclease Xrn2. A combination of complementary fluorine and methyl-TROSY NMR spectroscopy reveals that the apo enzyme is highly dynamic around the catalytic center. These observed dynamics are in agreement with a transition of the enzyme from the ground state into a catalytically competent state. We show that the conformational equilibrium in Xrn2 shifts substantially toward the active state in the presence of substrate and magnesium. Finally, our data reveal that the dynamics in Xrn2 correlate with the RNA degradation rate, as a mutation that attenuates motions also affects catalytic activity. In that light, our results stress the importance of studies that go beyond static structural information.
核磁共振（NMR）方法可定量探测分子和原子水平上的运动，从而推动了对静态结构无法提供满意描述的生物分子过程的理解。在这项工作中，我们研究了必需的 100kDa 真核 5'→3'外切核糖核酸酶 Xrn2 的结构和动力学。氟和甲基-TROSY NMR 光谱学的组合揭示了apo 酶在催化中心周围具有高度动态性。这些观察到的动力学与酶从基态向催化活性状态的转变一致。我们表明，在存在底物和镁的情况下，Xrn2 中的构象平衡会向活性状态发生显著转变。最后，我们的数据表明，Xrn2 中的动力学与 RNA 降解速率相关，因为削弱运动的突变也会影响催化活性。有鉴于此，我们的结果强调了超越静态结构信息的研究的重要性。
