Mechanism of CcdA-Mediated Rejuvenation of DNA Gyrase
Mechanism of CcdA-Mediated Rejuvenation of DNA Gyrase
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DOI：
10.1016/j.str.2020.03.006
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发表时间：
2020-05-05
期刊：
影响因子：
5.7
通讯作者：
Varadarajan, Raghavan
中科院分区：
文献类型：
--
作者：
Aghera, Nilesh K.;Prabha, Jyothi;Varadarajan, Raghavan
大多数生物学过程涉及瞬时复合物的形成，其中配体的结合变构调节功能。ccd毒素-抗毒素系统参与质粒的维持和细菌的持久性。CcdA抗毒素加速CcdB从其与DNA促旋酶的复合物中解离，结合并中和CcdB，但其机制细节尚不清楚。使用一系列的实验和计算方法，我们证明了形成的瞬态三元和四元CcdA：CcdB：促旋酶复合物，并描绘的分子步骤中所涉及的复兴过程。CcdA的区域61-72与CcdB的结合诱导促进从促旋酶解离所需的重要结构和动力学变化，区域50-60通过额外的变构效应增强解离过程，并且区段37-49防止促旋酶再结合。这项研究提供了对负责从持久性状态恢复CcdB中毒细胞的分子机制的见解。类似的方法可用于表征其他重要的瞬时大分子复合物。
Most biological processes involve formation of transient complexes where binding of a ligand allosterically modulates function. The ccd toxin-antitoxin system is involved in plasmid maintenance and bacterial persistence. The CcdA antitoxin accelerates dissociation of CcdB from its complex with DNA gyrase, binds and neutralizes CcdB, but the mechanistic details are unclear. Using a series of experimental and computational approaches, we demonstrate the formation of transient ternary and quaternary CcdA:CcdB:gyrase complexes and delineate the molecular steps involved in the rejuvenation process. Binding of region 61-72 of CcdA to CcdB induces the vital structural and dynamic changes required to facilitate dissociation from gyrase, region 50-60 enhances the dissociation process through additional allosteric effects, and segment 37-49 prevents gyrase rebinding. This study provides insights into molecular mechanisms responsible for recovery of CcdB-poisoned cells from a persister-like state. Similar methodology can be used to characterize other important transient, macromolecular complexes.