Sliding Clamps: An Open and Shut Case?
نویسندگان
چکیده
Molecular events in the clamp-loading reaction pathway of DNA replication are revealed by new crystal structures of bacteriophage T4 clamp loader-clamp-DNA complexes that capture two distinct conformations with the clamp open and closed.
منابع مشابه
The 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 کاملMechanism 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 کاملDynamics of Open DNA Sliding Clamps.
A range of enzymes in DNA replication and repair bind to DNA-clamps: torus-shaped proteins that encircle double-stranded DNA and act as mobile tethers. Clamps from viruses (such as gp45 from the T4 bacteriophage) and eukaryotes (PCNAs) are homotrimers, each protomer containing two repeats of the DNA-clamp motif, while bacterial clamps (pol III β) are homodimers, each protomer containing three D...
متن کاملRegulation of Interactions with Sliding Clamps During DNA Replication and Repair
The molecular machines that replicate the genome consist of many interacting components. Essential to the organization of the replication machinery are ring-shaped proteins, like PCNA (Proliferating Cell Nuclear Antigen) or the beta- clamp, collectively named sliding clamps. They encircle the DNA molecule and slide on it freely and bidirectionally. Sliding clamps are typically associated to DNA...
متن کاملA flexible interface between DNA ligase and PCNA supports conformational switching and efficient ligation of DNA.
DNA sliding clamps encircle DNA and provide binding sites for many DNA-processing enzymes. However, it is largely unknown how sliding clamps like proliferating cell nuclear antigen (PCNA) coordinate multistep DNA transactions. We have determined structures of Sulfolobus solfataricus DNA ligase and heterotrimeric PCNA separately by X-ray diffraction and in complex by small-angle X-ray scattering...
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ورودعنوان ژورنال:
- Current Biology
دوره 22 شماره
صفحات -
تاریخ انتشار 2012