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

Journal Article


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Abstract


  • 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.

Authors


  •   Berghuis, Bojk A. (external author)
  •   Dulin, David (external author)
  •   Xu, Zhi-Qiang
  •   van Laar, Theo (external author)
  •   Cross, Bronwen (external author)
  •   Janissen, Richard (external author)
  •   Jergic, Slobodan
  •   Dixon, Nicholas E.
  •   Depken, Martin (external author)
  •   Dekker, Nynke H. (external author)

Publication Date


  • 2015

Citation


  • Berghuis, 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.

Scopus Eid


  • 2-s2.0-84937729550

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=4013&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2991

Number Of Pages


  • 6

Start Page


  • 579

End Page


  • 585

Volume


  • 11

Issue


  • 8

Abstract


  • 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.

Authors


  •   Berghuis, Bojk A. (external author)
  •   Dulin, David (external author)
  •   Xu, Zhi-Qiang
  •   van Laar, Theo (external author)
  •   Cross, Bronwen (external author)
  •   Janissen, Richard (external author)
  •   Jergic, Slobodan
  •   Dixon, Nicholas E.
  •   Depken, Martin (external author)
  •   Dekker, Nynke H. (external author)

Publication Date


  • 2015

Citation


  • Berghuis, 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.

Scopus Eid


  • 2-s2.0-84937729550

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=4013&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/2991

Number Of Pages


  • 6

Start Page


  • 579

End Page


  • 585

Volume


  • 11

Issue


  • 8