Nanoscale interaction of RecG with mobile fork DNA

Zhiqiang Sun, Yaqing Wang, Piero R. Bianco, Yuri L. Lyubchenko

Research output: Contribution to journalArticle

Abstract

RecG DNA helicase is a guardian of the bacterial genome where it dominates stalled DNA replication fork rescue. The single-stranded DNA binding protein (SSB) is involved in this process and promotes the binding of RecG to stalled replication forks. Atomic force microscopy (AFM) was used to investigate the interaction of RecG and SSB on a mobile fork substrate capable of being regressed. In the absence of proteins, the fork undergoes spontaneous dynamics between two states, defined by the length of the DNA complementarity at the fork. The binding of SSB does not affect these dynamics as it binds to single-stranded regions as expected. In contrast, RecG interacts with the two states quite differently. We demonstrate that RecG has two modes of interaction with fork DNA in the presence of SSB and ATP. In the first mode, RecG translocates over the duplex region and this activity is defined by SSB-mediated remodeling of helicase. In the second mode, RecG utilizes its helicase activity to regress the fork, in an ATP-dependent manner, displacing SSB on the ssDNA. Overall, our results highlight two functions of RecG that can be employed in the regulation of stalled DNA replication fork rescue.

Original languageEnglish (US)
Pages (from-to)1318-1324
Number of pages7
JournalNanoscale Advances
Volume2
Issue number3
DOIs
StatePublished - Mar 2020

ASJC Scopus subject areas

  • Engineering(all)
  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Chemistry(all)

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