Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
DNA Replication Laboratory, The Rockefeller University, New York, NY, USA.
FEBS J. 2021 Dec;288(24):7256-7262. doi: 10.1111/febs.15740. Epub 2021 Feb 18.
Polymerase sliding clamps are ring-shaped proteins that encircle duplex DNA and hold polymerases to DNA for high processivity during synthesis. The crystal structure of clamp-DNA complex reveals that the DNA is highly tilted through the clamp with extensive interaction with the clamp inner surface. In contrast to the tilted clamp-DNA interaction without DNA polymerases, recent structures of replicative polymerases of bacteria, eukaryotes, and archaea that are bound to the clamp and DNA show that the polymerase positions DNA straight through the clamp without direct protein-DNA contacts. Instead, the clamp-to-DNA interaction is mediated by one or two layers of water. Hence, clamps 'water skate' on DNA during function with replicative polymerases from all domains of life, providing a nearly frictionless bearing for fast and processive DNA synthesis.
聚合酶滑动夹是一种环状蛋白质，可环绕双链 DNA，并在合成过程中将聚合酶固定在 DNA 上，以保持高的持续性。夹-DNA 复合物的晶体结构表明，DNA 高度倾斜穿过夹，与夹内表面广泛相互作用。与没有 DNA 聚合酶的倾斜夹-DNA 相互作用不同，最近细菌、真核生物和古菌复制聚合酶与夹和 DNA 结合的结构表明，聚合酶将 DNA 直接置于夹中，没有直接的蛋白-DNA 接触。相反，夹-DNA 相互作用由一层或两层水介导。因此，在所有生命领域的复制聚合酶的作用下，夹“在 DNA 上滑水”，为快速和持续性 DNA 合成提供了几乎无摩擦的轴承。
