Slow unloading leads to DNA-bound β2-sliding clamp accumulation in live Escherichia coli cells.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 25520215.
- Also identified by DOI 10.1038/ncomms6820 and PMC identifier 4284645.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The ubiquitous sliding clamp facilitates processivity of the replicative polymerase and acts as a platform to recruit proteins involved in replication, recombination and repair. While the dynamics of the E. coli β2-sliding clamp have been characterized in vitro, its in vivo stoichiometry and dynamics remain unclear. To probe both β2-clamp dynamics and stoichiometry in live E. coli cells, we use custom-built microfluidics in combination with single-molecule fluorescence microscopy and photoactivated fluorescence microscopy. We quantify the recruitment, binding and turnover of β2-sliding clamps on DNA during replication. These quantitative in vivo results demonstrate that numerous β2-clamps in E. coli remain on the DNA behind the replication fork for a protracted period of time, allowing them to form a docking platform for other enzymes involved in DNA metabolism.
Medical subject headings
- DNA Repair
- DNA Replication
- DNA, Bacterial
- Escherichia coli