RecQ helicase triggers a binding mode change in the SSB–DNA complex to efficiently initiate DNA unwinding

Maria Mills, Gábor M. Harami, Yeonee Seol, Máté Gyimesi, Máté Martina, Zoltán J. Kovács, Mihály Kovács, Keir C. Neuman

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The single-stranded DNA binding protein (SSB) of Escherichia coli plays essential roles in maintaining genome integrity by sequestering ssDNA and mediating DNA processing pathways through interactions with DNA-processing enzymes. Despite its DNA-sequestering properties, SSB stimulates the DNA processing activities of some of its binding partners. One example is the genome maintenance protein RecQ helicase. Here, we determine the mechanistic details of the RecQ–SSB interaction using single-molecule magnetic tweezers and rapid kinetic experiments. Our results reveal that the SSB–RecQ interaction changes the binding mode of SSB, thereby allowing RecQ to gain access to ssDNA and facilitating DNA unwinding. Conversely, the interaction of RecQ with the SSB C-terminal tail increases the on-rate of RecQ–DNA binding and has a modest stimulatory effect on the unwinding rate of RecQ. We propose that this bidirectional communication promotes efficient DNA processing and explains how SSB stimulates rather than inhibits RecQ activity.

Original languageEnglish
Pages (from-to)11878-11890
Number of pages13
JournalNucleic acids research
Volume45
Issue number20
DOIs
Publication statusPublished - 2017

ASJC Scopus subject areas

  • Genetics

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    Mills, M., Harami, G. M., Seol, Y., Gyimesi, M., Martina, M., Kovács, Z. J., Kovács, M., & Neuman, K. C. (2017). RecQ helicase triggers a binding mode change in the SSB–DNA complex to efficiently initiate DNA unwinding. Nucleic acids research, 45(20), 11878-11890. https://doi.org/10.1093/nar/gkx939