引发酶诱导的构象转换控制细菌复制体的稳定性。
A Primase-Induced Conformational Switch Controls the Stability of the Bacterial Replisome.
机构信息
Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia; Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747, the Netherlands.
Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
出版信息
Mol Cell. 2020 Jul 2;79(1):140-154.e7. doi: 10.1016/j.molcel.2020.04.037. Epub 2020 May 27.
Recent studies of bacterial DNA replication have led to a picture of the replisome as an entity that freely exchanges DNA polymerases and displays intermittent coupling between the helicase and polymerase(s). Challenging the textbook model of the polymerase holoenzyme acting as a stable complex coordinating the replisome, these observations suggest a role of the helicase as the central organizing hub. We show here that the molecular origin of this newly found plasticity lies in the 500-fold increase in strength of the interaction between the polymerase holoenzyme and the replicative helicase upon association of the primase with the replisome. By combining in vitro ensemble-averaged and single-molecule assays, we demonstrate that this conformational switch operates during replication and promotes recruitment of multiple holoenzymes at the fork. Our observations provide a molecular mechanism for polymerase exchange and offer a revised model for the replication reaction that emphasizes its stochasticity.
最近对细菌 DNA 复制的研究表明，复制体是一个可以自由交换 DNA 聚合酶的实体，并显示出解旋酶和聚合酶之间间歇性的偶联。这些观察结果挑战了聚合酶全酶作为稳定复合物协调复制体的教科书模型，表明解旋酶起着中心组织枢纽的作用。我们在这里表明，这种新发现的可塑性的分子起源在于聚合酶全酶与复制解旋酶之间的相互作用强度增加了 500 倍，当引发酶与复制体结合时。通过结合体外均相和单分子测定，我们证明这种构象转换在复制过程中起作用，并促进多个全酶在叉处的募集。我们的观察结果为聚合酶交换提供了一个分子机制，并为强调其随机性的复制反应提供了一个修正模型。
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