Distinct architectural requirements for the parS centromeric sequence of the pSM19035 plasmid partition machinery

• Published in: eLife Vol. 11
• Main Authors: Volante, Andrea, Alonso, Juan Carlos, Mizuuchi, Kiyoshi
• Format: Journal Article
• Language: English
• Published: Cambridge eLife Sciences Publications Ltd 05-09-2022; eLife Sciences Publications, Ltd
• Subjects: Adenosine triphosphatase; Asymmetry; Biochemistry and Chemical Biology; Cell Biology; Cell division; chromosome segregation; Chromosomes; Gene expression; Heredity; ParABS system; plasmid partition; Plasmids; Proteins
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.79480

Three-component ParABS partition systems ensure stable inheritance of many bacterial chromosomes and low-copy-number plasmids. ParA localizes to the nucleoid through its ATP-dependent nonspecific DNA-binding activity, whereas centromere-like
parS
-DNA and ParB form partition complexes that activate ParA-ATPase to drive the system dynamics. The essential
parS
sequence arrangements vary among ParABS systems, reflecting the architectural diversity of their partition complexes. Here, we focus on the pSM19035 plasmid partition system that uses a ParB
pSM
of the ribbon-helix-helix (RHH) family. We show that
parS
pSM
with four or more contiguous ParB
pSM
-binding sequence repeats is required to assemble a stable ParA
pSM
-ParB
pSM
complex and efficiently activate the ParA
pSM
-ATPase, stimulating complex disassembly. Disruption of the contiguity of the
parS
pSM
sequence array destabilizes the ParA
pSM
-ParB
pSM
complex and prevents efficient ATPase activation. Our findings reveal the unique architecture of the pSM19035 partition complex and how it interacts with nucleoid-bound ParA
pSM
-ATP.