The human replisome is an elaborate arrangement of molecular machines responsible for accurate chromosome replication. At its heart is the CDC45-MCM-GINS (CMG) helicase, which, in addition to unwinding the parental DNA duplex, arranges many proteins including the leading-strand polymerase Pol ε, together with TIMELESS-TIPIN, CLASPIN and AND-1 that have key and varied roles in maintaining smooth replisome progression. How these proteins are coordinated in the human replisome is poorly understood. We have determined a 3.2 Å cryo-EM structure of a human replisome comprising CMG, Pol ε, TIMELESS-TIPIN, CLASPIN and AND-1 bound to replication fork DNA. The structure permits a detailed understanding of how AND-1, TIMELESS-TIPIN and Pol ε engage CMG, reveals how CLASPIN binds to multiple replisome components and identifies the position of the Pol ε catalytic domain. Furthermore, the intricate network of contacts contributed by MCM subunits and TIMELESS-TIPIN with replication fork DNA suggests a mechanism for strand separation.

中文翻译：

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人类复制体的结构显示了 DNA 复制机器的组织和相互作用

人类复制体是负责精确染色体复制的分子机器的精心排列。其核心是 CDC45-MCM-GINS (CMG) 解旋酶，它除了解开亲本 DNA 双链体之外，还排列许多蛋白质，包括前链聚合酶 Pol ε，以及 TIMELESS-TIPIN、CLASPIN 和 AND-1，在维持复制体顺利进展方面具有关键且不同的作用。人们对这些蛋白质如何在人类复制体中协调还知之甚少。我们确定了人类复制体的 3.2 Å 冷冻电镜结构，其中包含与复制叉 DNA 结合的 CMG、Pol ε、TIMELESS-TIPIN、CLASPIN 和 AND-1。通过该结构，可以详细了解 AND-1、TIMELESS-TIPIN 和 Pol ε 如何与 CMG 结合，揭示 CLASPIN 如何与多个复制体成分结合，并确定 Pol ε 催化结构域的位置。此外，MCM 亚基和具有复制叉 DNA 的 TIMELESS-TIPIN 所形成的复杂接触网络表明了一种链分离机制。