The Clamp Loader Assembles the β Clamp onto Either a 3′ or 5′ Primer Terminus
نویسندگان
چکیده
منابع مشابه
Dual functions, clamp opening and primer-template recognition, define a key clamp loader subunit.
Clamp loader proteins catalyze assembly of circular sliding clamps on DNA to enable processive DNA replication. During the reaction, the clamp loader binds primer-template DNA and positions it in the center of a clamp to form a topological link between the two. Clamp loaders are multi-protein complexes, such as the five protein Escherichia coli, Saccharomyces cerevisiae, and human clamp loaders...
متن کاملThe Escherichia coli Clamp Loader Can Actively Pry Open the β-Sliding Clamp*
Clamp loaders load ring-shaped sliding clamps onto DNA. Once loaded onto DNA, sliding clamps bind to DNA polymerases to increase the processivity of DNA synthesis. To load clamps onto DNA, an open clamp loader-clamp complex must form. An unresolved question is whether clamp loaders capture clamps that have transiently opened or whether clamp loaders bind closed clamps and actively open clamps. ...
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 کاملThe RFC clamp loader: structure and function.
The eukaryotic RFC clamp loader couples the energy of ATP hydrolysis to open and close the circular PCNA sliding clamp onto primed sites for use by DNA polymerases and repair factors. Structural studies reveal clamp loaders to be heteropentamers. Each subunit contains a region of homology to AAA+ proteins that defines two domains. The AAA+ domains form a right-handed spiral upon binding ATP. Th...
متن کاملThe Mechanism of ATP-Dependent Primer-Template Recognition by a Clamp Loader Complex
Clamp loaders load sliding clamps onto primer-template DNA. The structure of the E. coli clamp loader bound to DNA reveals the formation of an ATP-dependent spiral of ATPase domains that tracks only the template strand, allowing recognition of both RNA and DNA primers. Unlike hexameric helicases, in which DNA translocation requires distinct conformations of the ATPase domains, the clamp loader ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2009
ISSN: 0021-9258
DOI: 10.1074/jbc.m109.050310