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bioRxiv · 10.1101/2021.01.24.427996

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

Taylor, J. A.·Seol, Y.·Neuman, K. C.·Mizuuchi, K.
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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 ParBF and parSF move by generating and following a local concentration gradient of nucleoid-bound ParAF. However, the process through which ParBF activates ParAF-ATPase has not been defined. We studied CTP- and parSF-modulated ParAF--ParBF complex assembly, in which DNA-bound ParAF-ATP dimers are activated for ATP hydrolysis by interacting with two ParBF N-terminal domains. CTP or parSF enhances the ATPase rate without significantly accelerating ParAF--ParBF complex assembly. Together, parSF and CTP accelerate ParAF--ParBF assembly without further significant increase in ATPase rate. Magnetic-tweezers experiments showed that CTP promotes multiple ParBF loading onto parSF-containing DNA, generating condensed partition complex-like assemblies. We propose that ParBF in the partition complex adopts a conformation that enhances ParBF--ParBF and ParAF--ParBF interactions promoting efficient partitioning.

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Taylor, J. A., Seol, Y., Neuman, K. C., Mizuuchi, K.. 2021-01-25. CTP and parS control ParB partition complex dynamics and ParA-ATPase activation for ParABS-mediated DNA partitioning. https://doi.org/10.1101/2021.01.24.427996

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