Mechanism of termination of DNA replication of
            <i>Escherichia coli</i>
            involves helicase–contrahelicase interaction

Mulugu, Sashidhar; Potnis, Aardra; Shamsuzzaman, _; Taylor, Jeffery P.; Alexander, Ken; Bastia, Deepak

doi:10.1073/pnas.171065898

Cited by 70 publications

(98 citation statements)

References 27 publications

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“…The 'mousetrap' model of Tus-Ter RF pausing posits that a specific interaction is required between Tus and a critical 'locking cytosine' residue within TerB that is revealed by DNA strand separation 22 . An alternative model proposes that RF arrest at Tus-Ter is mediated by specific protein-protein interactions in E. coli 23,24 . Our data suggest that, although additional proteins may be required to reinforce RF pausing at Tus-Ter in E. coli 23,24 , these are clearly not required for Tus-Ter to function as a polar RF barrier in yeast.…”

Section: Tus-ter Modules Cause Polar Rf Pausing In Yeast the 21-bpmentioning

confidence: 99%

The Escherichia coli Tus–Ter replication fork barrier causes site-specific DNA replication perturbation in yeast

et al. 2014

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Replication fork (RF) pausing occurs at both 'programmed' sites and non-physiological barriers (for example, DNA adducts). Programmed RF pausing is required for site-specific DNA replication termination in Escherichia coli, and this process requires the binding of the polar terminator protein, Tus, to specific DNA sequences called Ter. Here, we demonstrate that Tus-Ter modules also induce polar RF pausing when engineered into the Saccharomyces cerevisiae genome. This heterologous RF barrier is distinct from a number of previously characterized, protein-mediated, RF pause sites in yeast, as it is neither Tof1-dependent nor counteracted by the Rrm3 helicase. Although the yeast replisome can overcome RF pausing at Tus-Ter modules, this event triggers site-specific homologous recombination that requires the RecQ helicase, Sgs1, for its timely resolution. We propose that Tus-Ter can be utilized as a versatile, site-specific, heterologous DNA replication-perturbing system, with a variety of potential applications.

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Section: Tus-ter Modules Cause Polar Rf Pausing In Yeast the 21-bpmentioning

confidence: 99%

The Escherichia coli Tus–Ter replication fork barrier causes site-specific DNA replication perturbation in yeast

et al. 2014

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“…We further observed that mutant E49K, which is hypothesized to be deficient in polar replication fork arrest due to the elimination of specific protein-protein interactions 13,14 , gave rise to lifetimes identical to that of wt Tus, only now with a severely decreased probability of entering the longest-lived state. This ties the observed deficiency of in vivo fork arrest to the drop in occurrence of the longest-lived state found in our experiments.…”

Section: Discussionmentioning

confidence: 72%

“…A more direct link between our probabilities and in vivo arrest efficiencies will require knowledge of, for example, the amount of work performed by a replisome. It remains to be determined to what extent the two shortest-lived lock states are capable of causing arrest of DNA-processing enzymes, though the reported replisome arrest deficiency of E49K 13,14 together with our observation that E49K affects only the longest-lived state, suggests that these intermediate states are not sufficient to block replication fork progression. It is clear though that these two 'lesser' lock states still pose a significant barrier to strand separation, much more so than the mere binding of Tus alone.…”

Section: Discussionmentioning

confidence: 85%

“…Tus-Ter is much more effective in its natural host for instance, while the functionally similar but structurally unrelated Bacillus subtilis replication termination system works well in E. coli 11,12 . Tus-Ter blocks DnaB in vitro, but not the Rep helicase 13 , and evidence from yeast two-hybrid analysis shows specific interactions between DnaB and Tus 14 . On the other hand, ample evidence suggests a protein-independent polar blocking mechanism.…”

Section: Introductionmentioning

confidence: 94%

“…3a, orange). Residue E49, linked to the putative specific protein-protein interaction between Tus and the E. coli DnaB helicase 13,14 , lies just outside the lock domain ( Supplementary Fig. 3d, in green), though it does make a water-mediated hydrogen-bonding contact with the 5'-phosphate of A7 in the locked complex 21 .…”

Section: Probing Mechanism Via Mutations In or Near The Lock Domainmentioning

confidence: 99%

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Strand separation establishes a sustained lock at the Tus–Ter replication fork barrier

Berghuis

Dulin

et al. 2015

Nat Chem Biol

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The bidirectional replication of a circular chromosome by many bacteria necessitates proper termination to avoid the head-on collision of the opposing replisomes. In Escherichia coli, replisome progression beyond the termination site is prevented by Tus proteins bound to asymmetric Ter sites. Structural evidence indicates that strand separation on the blocking (nonpermissive) side of Tus-Ter triggers roadblock formation, but biochemical evidence also suggests roles for protein-protein interactions. Here DNA unzipping experiments demonstrate that nonpermissively oriented Tus-Ter forms a tight lock in the absence of replicative proteins, whereas permissively oriented Tus-Ter allows nearly unhindered strand separation. Quantifying the lock strength reveals the existence of several intermediate lock states that are impacted by mutations in the lock domain but not by mutations in the DNA-binding domain. Lock formation is highly specific and exceeds reported in vivo efficiencies. We postulate that protein-protein interactions may actually hinder, rather than promote, proper lock formation. Disciplines Medicine and Health Sciences | Social and Behavioral Sciences Publication DetailsBerghuis, B. A., Dulin, D., Xu, Z., van Laar, T., Cross, B., Janissen, R., Jergic, S., Dixon, N. E., Depken, M. & Dekker, N. H. (2015). Strand separation establishes a sustained lock at the Tus-Ter replication fork barrier. Nature Chemical Biology, 11 (8), 579-585. Authors

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Termination ofDNAReplication in Prokaryotes

Rudolph

Corocher

Grainge

et al. 2019

Encyclopedia of Life Sciences

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Most bacteria and archaea have circular chromosomes, in which DNA replication begins at a site known as an origin of replication. Double-stranded DNA unwound at the origin creates two replication forks that are engaged by DNA polymerase complexes (replisomes) that advance each fork and proceed in 21 opposite directions away from the origin, copying the original strands. Termination of DNA replication 22 occurs when the two forks meet and fuse, creating two separate double-stranded DNA molecules. In 23 the well-studied bacteria Escherichia coli and Bacillus subtilis, this occurs in the terminus region, which is situated diametrically opposite the origin. Failure to terminate chromosome replication correctly can lead to problems with genome function and stability, including DNA over-replication. In contrast, some 26 archaea have multi-origin chromosomes and do not appear to specifically regulate the location of termination.

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Mechanism of termination of DNA replication of Escherichia coli involves helicase–contrahelicase interaction

Abstract: protein-protein interaction ͉ replication arrest ͉ two-hybrid analysis ͉ reverse two-hybrid analysis

Cited by 70 publications

References 27 publications

The Escherichia coli Tus–Ter replication fork barrier causes site-specific DNA replication perturbation in yeast

The Escherichia coli Tus–Ter replication fork barrier causes site-specific DNA replication perturbation in yeast

Strand separation establishes a sustained lock at the Tus–Ter replication fork barrier

Termination ofDNAReplication in Prokaryotes

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