Structural highlights
Function
LOADL_BPT4 Forms the sliding-clamp-loader together with the small subunit (PubMed:10585481). Functions as an ATPase enzyme (PubMed:16800623, PubMed:18676368). The clamp loader holds the clamp in an open conformation and places it onto the DNA (PubMed:18676368, PubMed:22194570). 4 ATP molecules must bind to the sliding-clamp-loader before the latter can open the sliding clamp (PubMed:18676368). ATP hydrolysis triggers the detachment of the sliding clamp from the sliding-clamp-loader, freeing the sliding clamp to track along DNA (PubMed:18676368, PubMed:22194570).[HAMAP-Rule:MF_04162][1] [2] [3] [4]
Publication Abstract from PubMed
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.
How a DNA polymerase clamp loader opens a sliding clamp.,Kelch BA, Makino DL, O'Donnell M, Kuriyan J Science. 2011 Dec 23;334(6063):1675-80. PMID:22194570[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Janzen DM, Torgov MY, Reddy MK. In vitro reconstitution of the bacteriophage T4 clamp loader complex (gp44/62). J Biol Chem. 1999 Dec 10;274(50):35938-43. PMID:10585481 doi:10.1074/jbc.274.50.35938
- ↑ Zhuang Z, Berdis AJ, Benkovic SJ. An alternative clamp loading pathway via the T4 clamp loader gp44/62-DNA complex. Biochemistry. 2006 Jul 4;45(26):7976-89. PMID:16800623 doi:http://dx.doi.org/10.1021/bi0601205
- ↑ Pietroni P, von Hippel PH. Multiple ATP binding is required to stabilize the "activated" (clamp open) clamp loader of the T4 DNA replication complex. J Biol Chem. 2008 Oct 17;283(42):28338-53. doi: 10.1074/jbc.M804371200. Epub 2008, Aug 1. PMID:18676368 doi:http://dx.doi.org/10.1074/jbc.M804371200
- ↑ Kelch BA, Makino DL, O'Donnell M, Kuriyan J. How a DNA polymerase clamp loader opens a sliding clamp. Science. 2011 Dec 23;334(6063):1675-80. PMID:22194570 doi:10.1126/science.1211884
- ↑ Kelch BA, Makino DL, O'Donnell M, Kuriyan J. How a DNA polymerase clamp loader opens a sliding clamp. Science. 2011 Dec 23;334(6063):1675-80. PMID:22194570 doi:10.1126/science.1211884
