Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; Université Paris Diderot, Sorbonne Paris Cité, 75724 Paris Cedex 15, France.
Sorbonne Université, Centre d'Immunologie et des Maladies Infectieuses-Paris, Cimi-Paris, INSERM U1135, National Reference Center for Mycobacteria, Laboratoire de Bactériologie-Hygiène, AP-HP, Hôpitaux Universitaires Pitié-Salpêtrière - Charles Foix, 75013 Paris, France.
Structure. 2019 Apr 2;27(4):579-589.e5. doi: 10.1016/j.str.2019.01.004. Epub 2019 Feb 7.
Despite sharing common features, previous studies have shown that gyrases from different species have been modified throughout evolution to modulate their properties. Here, we report two crystal structures of Mycobacterium tuberculosis DNA gyrase, an apo and AMPPNP-bound form at 2.6-Å and 3.3-Å resolution, respectively. These structures provide high-resolution structural data on the quaternary organization and interdomain connections of a gyrase (full-length GyrB-GyrA57) thus providing crucial inputs on this essential drug target. Together with small-angle X-ray scattering studies, they revealed an "extremely open" N-gate state, which persists even in the DNA-free gyrase-AMPPNP complex and an unexpected connection between the ATPase and cleavage core domains mediated by two Corynebacteriales-specific motifs, respectively the C-loop and DEEE-loop. We show that the C-loop participates in the stabilization of this open conformation, explaining why this gyrase has a lower ATPase activity. Our results image a conformational state which might be targeted for drug discovery.
尽管具有共同特征，但之前的研究表明，不同物种的拓扑异构酶在进化过程中已经发生了修饰，以调节其性质。在这里，我们报告了结核分枝杆菌 DNA 拓扑异构酶的两种晶体结构，分别为 apo 和 AMPPNP 结合形式，分辨率分别为 2.6-Å 和 3.3-Å。这些结构提供了关于拓扑异构酶（全长 GyrB-GyrA57）四级组织和结构域间连接的高分辨率结构数据，从而为这一重要药物靶标提供了关键信息。与小角 X 射线散射研究相结合，它们揭示了一种“极其开放”的 N 门状态，即使在无 DNA 的拓扑异构酶-AMPPNP 复合物中也保持不变，以及由两个棒状杆菌科特异性模体（分别为 C 环和 DEEE 环）介导的 ATP 酶和切割核心结构域之间的意外连接。我们表明 C 环参与了这种开放构象的稳定，解释了为什么这种拓扑异构酶的 ATP 酶活性较低。我们的结果描绘了一种可能成为药物发现目标的构象状态。
