A Primase-Induced Conformational Switch Controls the Stability of the Bacterial Replisome

Enrico Monachino, Slobodan Jergic, Jacob S. Lewis, Zhi Qiang Xu, Allen T.Y. Lo, Valerie L. O'Shea, James M. Berger, Nicholas E. Dixon, Antoine M. van Oijen

Research output: Contribution to journalArticle

Abstract

Recent studies of bacterial DNA replication have led to a picture of the replisome as an entity that freely exchanges DNA polymerases and displays intermittent coupling between the helicase and polymerase(s). Challenging the textbook model of the polymerase holoenzyme acting as a stable complex coordinating the replisome, these observations suggest a role of the helicase as the central organizing hub. We show here that the molecular origin of this newly found plasticity lies in the 500-fold increase in strength of the interaction between the polymerase holoenzyme and the replicative helicase upon association of the primase with the replisome. By combining in vitro ensemble-averaged and single-molecule assays, we demonstrate that this conformational switch operates during replication and promotes recruitment of multiple holoenzymes at the fork. Our observations provide a molecular mechanism for polymerase exchange and offer a revised model for the replication reaction that emphasizes its stochasticity.

Original languageEnglish (US)
JournalMolecular cell
DOIs
StateAccepted/In press - 2020

Keywords

  • DNA replication
  • DnaB helicase
  • DnaG primase
  • clamp loader-helicase interaction
  • conformational switch
  • polymerase turnover

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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    Monachino, E., Jergic, S., Lewis, J. S., Xu, Z. Q., Lo, A. T. Y., O'Shea, V. L., Berger, J. M., Dixon, N. E., & van Oijen, A. M. (Accepted/In press). A Primase-Induced Conformational Switch Controls the Stability of the Bacterial Replisome. Molecular cell. https://doi.org/10.1016/j.molcel.2020.04.037