3u60
From Proteopedia
Structure of T4 Bacteriophage Clamp Loader Bound To Open Clamp, DNA and ATP Analog
Structural highlights
Function[DPA62_BPT4] Function as a sliding-clamp-loading ATPase enzyme during DNA replication. Required for elongation of primed templates by controlling the polymerase processivity. Progressive binding of ATPs triggers a conformational change in the complex that inhibits ATPase activity. [DPA44_BPT4] Function as a sliding-clamp-loading ATPase enzyme during DNA replication. Required for elongation of primed templates by controlling the polymerase processivity. Possesses DNA-dependent ATPase activity on its own and within the heterodimer gp44/gp62. Progressive binding of ATPs triggers a conformational change in the complex that inhibits ATPase activity.[1] [2] [DPA5_BPT4] Replisome sliding clamp subunit. Responsible for tethering the catalytic subunit of DNA polymerase to DNA during high-speed replication. Publication Abstract from PubMedProcessive 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[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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