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Two mechanisms coordinate replication termination by the Escherichia coli Tus-Ter complex

Journal Article


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Abstract


  • The Escherichia coli replication terminator protein (Tus) binds to Ter sequences to block replication forks approaching from one direction. Here, we used single molecule and transient state kinetics to study responses of the heterologous phage T7 replisome to the Tus–Ter complex. The T7 replisome was arrested at the non-permissive end of Tus–Ter in a manner that is explained by a composite mousetrap and dynamic clamp model. An unpaired C(6) that forms a lock by binding into the cytosine binding pocket of Tus was most effective in arresting the replisome and mutation of C(6) removed the barrier. Isolated helicase was also blocked at the non-permissive end, but unexpectedly the isolated polymerase was not, unless C(6) was unpaired. Instead, the polymerase was blocked at the permissive end. This indicates that the Tus–Ter mechanism is sensitive to the translocation polarity of the DNA motor. The polymerase tracking along the template strand traps the C(6) to prevent lock formation; the helicase tracking along the other strand traps the complementary G(6) to aid lock formation. Our results are consistent with the model where strand separation by the helicase unpairs the GC(6) base pair and triggers lock formation immediately before the polymerase can sequester the C(6) base.

Authors


  •   Pandey, Manjula (external author)
  •   Elshenawy, Mohamed M. (external author)
  •   Jergic, Slobodan
  •   Takahashi, Masateru (external author)
  •   Dixon, Nicholas E.
  •   Hamdan, Samir M. (external author)
  •   Patel, Smita S. (external author)

Publication Date


  • 2015

Citation


  • Pandey, M., Elshenawy, M. M., Jergic, S., Takahashi, M., Dixon, N. E., Hamdan, S. M. & Patel, S. S. (2015). Two mechanisms coordinate replication termination by the Escherichia coli Tus-Ter complex. Nucleic Acids Research, 43 (12), 5924-5935.

Scopus Eid


  • 2-s2.0-84942068460

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=4145&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/3122

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 5924

End Page


  • 5935

Volume


  • 43

Issue


  • 12

Place Of Publication


  • United Kingdom

Abstract


  • The Escherichia coli replication terminator protein (Tus) binds to Ter sequences to block replication forks approaching from one direction. Here, we used single molecule and transient state kinetics to study responses of the heterologous phage T7 replisome to the Tus–Ter complex. The T7 replisome was arrested at the non-permissive end of Tus–Ter in a manner that is explained by a composite mousetrap and dynamic clamp model. An unpaired C(6) that forms a lock by binding into the cytosine binding pocket of Tus was most effective in arresting the replisome and mutation of C(6) removed the barrier. Isolated helicase was also blocked at the non-permissive end, but unexpectedly the isolated polymerase was not, unless C(6) was unpaired. Instead, the polymerase was blocked at the permissive end. This indicates that the Tus–Ter mechanism is sensitive to the translocation polarity of the DNA motor. The polymerase tracking along the template strand traps the C(6) to prevent lock formation; the helicase tracking along the other strand traps the complementary G(6) to aid lock formation. Our results are consistent with the model where strand separation by the helicase unpairs the GC(6) base pair and triggers lock formation immediately before the polymerase can sequester the C(6) base.

Authors


  •   Pandey, Manjula (external author)
  •   Elshenawy, Mohamed M. (external author)
  •   Jergic, Slobodan
  •   Takahashi, Masateru (external author)
  •   Dixon, Nicholas E.
  •   Hamdan, Samir M. (external author)
  •   Patel, Smita S. (external author)

Publication Date


  • 2015

Citation


  • Pandey, M., Elshenawy, M. M., Jergic, S., Takahashi, M., Dixon, N. E., Hamdan, S. M. & Patel, S. S. (2015). Two mechanisms coordinate replication termination by the Escherichia coli Tus-Ter complex. Nucleic Acids Research, 43 (12), 5924-5935.

Scopus Eid


  • 2-s2.0-84942068460

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=4145&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/3122

Has Global Citation Frequency


Number Of Pages


  • 11

Start Page


  • 5924

End Page


  • 5935

Volume


  • 43

Issue


  • 12

Place Of Publication


  • United Kingdom