منابع مشابه
Mechanism of opening a sliding clamp
Clamp loaders load ring-shaped sliding clamps onto DNA where the clamps serve as processivity factors for DNA polymerases. In the first stage of clamp loading, clamp loaders bind and stabilize clamps in an open conformation, and in the second stage, clamp loaders place the open clamps around DNA so that the clamps encircle DNA. Here, the mechanism of the initial clamp opening stage is investiga...
متن کاملMechanism of the Sliding @ - Clamp of DNA Polymerase I 11
DNA polymerase I11 holoenzyme (holoenzyme), the multiprotein replicase of Escherichia coli, is essentially unlimited in processive DNA synthesis. Processive activity can be reconstituted from two components. One component, the @ preinitiation complex, is a @ dimer clamped onto primed DNA. The @ preinitiation complex is formed by the five-protein y complex, which hydrolyzes ATP to chaperone @ on...
متن کاملHow a DNA polymerase clamp loader opens a sliding clamp.
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 ope...
متن کاملInterplay of clamp loader subunits in opening the beta sliding clamp of Escherichia coli DNA polymerase III holoenzyme.
The Escherichia coli beta dimer is a ring-shaped protein that encircles DNA and acts as a sliding clamp to tether the replicase, DNA polymerase III holoenzyme, to DNA. The gamma complex (gammadeltadelta'chipsi) clamp loader couples ATP to the opening and closing of beta in assembly of the ring onto DNA. These proteins are functionally and structurally conserved in all cells. The eukaryotic equi...
متن کاملStructure of a Sliding Clamp on DNA
The structure of the E. coli beta clamp polymerase processivity factor has been solved in complex with primed DNA. Interestingly, the clamp directly binds the DNA duplex and also forms a crystal contact with the ssDNA template strand, which binds into the protein-binding pocket of the clamp. We demonstrate that these clamp-DNA interactions function in clamp loading, perhaps by inducing the ring...
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ژورنال
عنوان ژورنال: Nucleic Acids Research
سال: 2017
ISSN: 0305-1048,1362-4962
DOI: 10.1093/nar/gkx665