CTP and parS coordinate ParB partition complex dynamics and ParA-ATPase activation for ParABS-mediated DNA partitioning

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Abstract

ParABS partition systems, comprising the centromere-like DNA sequence parS, the parS-binding ParB-CTPase and the nucleoid-binding ParA-ATPase, ensure faithful segregation of bacterial chromosomes and low-copy-number plasmids. F-plasmid partition complexes containing ParB_F and parS_F move by generating and following a local concentration gradient of nucleoid-bound ParA_F. However, the process through which ParB_F activates ParA_F-ATPase has not been defined. We studied CTP- and parS_F-modulated ParA_F-ParB_F complex assembly, in which DNA-bound ParA_F-ATP dimers are activated for ATP hydrolysis by interacting with two ParB_F N-terminal domains. CTP or parS_F enhances the ATPase rate without significantly accelerating ParA_F-ParB_F complex assembly. Together, parS_F and CTP accelerate ParA_F-ParB_F assembly without further significant increase in ATPase rate. Magnetic-tweezers experiments showed that CTP promotes multiple ParB_F loading onto parS_F-containing DNA, generating condensed partition complex-like assemblies. We propose that ParB_F in the partition complex adopts a conformation that enhances ParB_F-ParB_F and ParA_F-ParB_F interactions promoting efficient partitioning.

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All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for all relevant figures.

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James A Taylor

Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom

Competing interests
The authors declare that no competing interests exist.
Yeonee Seol

Laboratory of Single Molecule Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States

Competing interests
The authors declare that no competing interests exist.
Jagat Budhathoki

NIDDK/NIH, Bethesda, United States

Competing interests
The authors declare that no competing interests exist.
Keir C Neuman

National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-0863-5671
Kiyoshi Mizuuchi

NIDDK/NIH, Bethesda, United States

For correspondence
kiyoshimi@niddk.nih.gov

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-8193-9244

Funding

NIDDK/NIH (Intramural Research Fund)

Kiyoshi Mizuuchi

NHLBI/NIH (Intramural Research Fund)

Keir C Neuman

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.