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4xr0

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Escherichia Coli Replication Terminator Protein (Tus) Complexed With DNA- G/T mismatch.

Structural highlights

4xr0 is a 3 chain structure with sequence from Escherichia coli and Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.8Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TUS_ECOLI Trans-acting protein required for termination of DNA replication. Binds to DNA replication terminator sequences (terA to terF) to prevent the passage of replication forks. The termination efficiency will be affected by the affinity of this protein for the terminator sequence.

Publication Abstract from PubMed

In all domains of life, DNA synthesis occurs bidirectionally from replication origins. Despite variable rates of replication fork progression, fork convergence often occurs at specific sites. Escherichia coli sets a 'replication fork trap' that allows the first arriving fork to enter but not to leave the terminus region. The trap is set by oppositely oriented Tus-bound Ter sites that block forks on approach from only one direction. However, the efficiency of fork blockage by Tus-Ter does not exceed 50% in vivo despite its apparent ability to almost permanently arrest replication forks in vitro. Here we use data from single-molecule DNA replication assays and structural studies to show that both polarity and fork-arrest efficiency are determined by a competition between rates of Tus displacement and rearrangement of Tus-Ter interactions that leads to blockage of slower moving replisomes by two distinct mechanisms. To our knowledge this is the first example where intrinsic differences in rates of individual replisomes have different biological outcomes.

Replisome speed determines the efficiency of the Tus-Ter replication termination barrier.,Elshenawy MM, Jergic S, Xu ZQ, Sobhy MA, Takahashi M, Oakley AJ, Dixon NE, Hamdan SM Nature. 2015 Sep 17;525(7569):394-8. doi: 10.1038/nature14866. Epub 2015 Aug 31. PMID:26322585^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Elshenawy MM, Jergic S, Xu ZQ, Sobhy MA, Takahashi M, Oakley AJ, Dixon NE, Hamdan SM. Replisome speed determines the efficiency of the Tus-Ter replication termination barrier. Nature. 2015 Sep 17;525(7569):394-8. doi: 10.1038/nature14866. Epub 2015 Aug 31. PMID:26322585 doi:http://dx.doi.org/10.1038/nature14866