AI Article Synopsis
- Processive chromosomal replication uses sliding DNA clamps, which are loaded onto DNA by specialized clamp loader complexes that belong to a family of ATPases.
- Researchers presented structures showing the clamp loader complex from bacteriophage T4, highlighting how it binds to an open clamp and primer-template DNA in a spiral conformation that fits the helical structure of DNA.
- One structure shows ATP hydrolysis occurring in the loader, indicating that the process of closing the clamp and releasing the loader involves disrupting the ATP-dependent matching of symmetry, which is crucial for facilitating the release of the closed clamp onto the DNA.
Article 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.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3281585 | PMC |
| http://dx.doi.org/10.1126/science.1211884 | DOI Listing |
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