Summary information and primary citation

PDB-id
3u61; SNAP-derived features in text and JSON formats; DNAproDB
Class
DNA binding protein-DNA
Method
X-ray (3.2 Å)
Summary
Structure of t4 bacteriophage clamp loader bound to closed clamp, DNA and atp analog and adp
Reference
Kelch BA, Makino DL, O'Donnell M, Kuriyan J (2011): "How a DNA polymerase clamp loader opens a sliding clamp." Science, 334, 1675-1680. doi: 10.1126/science.1211884.
Abstract
Processive chromosomal replication relies on sliding DNA clamps, which are loaded onto DNA by pentameric clamp loader complexes belonging to the AAA+ family of adenosine triphosphatases (ATPases). We present structures for the ATP-bound state of the clamp loader complex from bacteriophage T4, bound to an open clamp and primer-template DNA. The clamp loader traps a spiral conformation of the open clamp so that both the loader and the clamp match the helical symmetry of DNA. One structure reveals that ATP has been hydrolyzed in one subunit and suggests that clamp closure and ejection of the loader involves disruption of the ATP-dependent match in symmetry. The structures explain how synergy among the loader, the clamp, and DNA can trigger ATP hydrolysis and release of the closed clamp on DNA.

Cartoon-block schematics in six views (download the tarball)

PyMOL session file Download PDB file View in 3Dmol.js