8VAN

Structure of the E. coli clamp loader bound to the beta clamp in an Initial-Binding conformation

8VAN の概要

• エントリーDOI: 10.2210/pdb8van/pdb
• 関連するPDBエントリー: 8VAL 8VAM 8VAP 8VAQ 8VAR 8VAS 8VAT
• EMDBエントリー: 43096
• 分子名称: DNA polymerase III subunit delta, DNA polymerase III subunit tau, DNA polymerase III subunit delta', ... (4 entities in total)
• 機能のキーワード: bacterial clamp loader complex, replication, transferase
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 7
• 化学式量合計: 283273.51

構造登録者

Landeck, J.T.,Pajak, J.,Kelch, B.A. (登録日: 2023-12-11, 公開日: 2024-03-27, 最終更新日: 2024-05-01)

主引用文献

Landeck, J.T.,Pajak, J.,Norman, E.K.,Sedivy, E.L.,Kelch, B.A.
Differences between bacteria and eukaryotes in clamp loader mechanism, a conserved process underlying DNA replication.
J.Biol.Chem., 300:107166-107166, 2024

PubMed Abstract: Clamp loaders are pentameric ATPases that place circular sliding clamps onto DNA, where they function in DNA replication and genome integrity. The central activity of a clamp loader is the opening of the ring-shaped sliding clamp and the subsequent binding to primer-template (p/t)-junctions. The general architecture of clamp loaders is conserved across all life, suggesting that their mechanism is retained. Recent structural studies of the eukaryotic clamp loader replication factor C (RFC) revealed that it functions using a crab-claw mechanism, where clamp opening is coupled to a massive conformational change in the loader. Here we investigate the clamp loading mechanism of the Escherichia coli clamp loader at high resolution using cryo-electron microscopy. We find that the E. coli clamp loader opens the clamp using a crab-claw motion at a single pivot point, whereas the eukaryotic RFC loader uses motions distributed across the complex. Furthermore, we find clamp opening occurs in multiple steps, starting with a partly open state with a spiral conformation, and proceeding to a wide open clamp in a surprising planar geometry. Finally, our structures in the presence of p/t-junctions illustrate how the clamp closes around p/t-junctions and how the clamp loader initiates release from the loaded clamp. Our results reveal mechanistic distinctions in a macromolecular machine that is conserved across all domains of life.

PubMed: 38490435
DOI: 10.1016/j.jbc.2024.107166

実験手法

ELECTRON MICROSCOPY (7.7 Å)