Dataset Information

Molecular Anatomy of ParA-ParA and ParA-ParB Interactions during Plasmid Partitioning.

ABSTRACT: Firmicutes multidrug resistance inc18 plasmids encode parS sites and two small homodimeric ParA-like (?2) and ParB-like (?2) proteins to ensure faithful segregation. Protein ?2 binds to parS DNA, forming a short left-handed helix wrapped around the full parS, and interacts with ?2. Protein ?2 interacts with ?2 and, in the ATP-bound form, binds to nonspecific DNA (nsDNA), forming small clusters. Here, we have mapped the ?2·?2 and ?2·?2 interacting domains in the ?2 that are adjacent to but distinct from each other. The ?2 nsDNA binding domain is essential for stimulation of ?2·parS-mediated ATP hydrolysis. From the data presented here, we propose that ?2 interacts with ATP, nsDNA, and with ?2 bound to parS at near equimolar concentrations, facilitating a ?2 structural transition. This ?2 "activated" state overcomes its impediment in ATP hydrolysis, with the subsequent release of both of the proteins from nsDNA (plasmid unpairing).

SUBMITTER: Volante A

PROVIDER: S-EPMC4513133 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature

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Publications

Molecular Anatomy of ParA-ParA and ParA-ParB Interactions during Plasmid Partitioning.

Volante Andrea A Alonso Juan C JC

The Journal of biological chemistry 20150608 30

Firmicutes multidrug resistance inc18 plasmids encode parS sites and two small homodimeric ParA-like (δ2) and ParB-like (ω2) proteins to ensure faithful segregation. Protein ω2 binds to parS DNA, forming a short left-handed helix wrapped around the full parS, and interacts with δ2. Protein δ2 interacts with ω2 and, in the ATP-bound form, binds to nonspecific DNA (nsDNA), forming small clusters. Here, we have mapped the ω2·δ2 and δ2·δ2 interacting domains in the δ2 that are adjacent to but distin ...[more]

PMID: 26055701

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Project description:In the majority of bacterial species, the tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target parS sequence(s), assists in the chromosome partitioning. ParB forms large nucleoprotein complexes at parS(s), located in the vicinity of origin of chromosomal replication (oriC), which after replication are subsequently positioned by ParA in cell poles. Remarkably, ParA and ParB participate not only in the chromosome segregation but through interactions with various cellular partners they are also involved in other cell cycle-related processes, in a species-specific manner. In this work, we characterized Pseudomonas aeruginosa ParB interactions with the cognate ParA, showing that the N-terminal motif of ParB is required for these interactions, and demonstrated that ParAB-parS-mediated rapid segregation of newly replicated ori domains prevented structural maintenance of chromosome (SMC)-mediated cohesion of sister chromosomes. Furthermore, using proteome-wide techniques, we have identified other ParB partners in P. aeruginosa, which encompass a number of proteins, including the nucleoid-associated proteins NdpA(PA3849) and NdpA2, MinE (PA3245) of Min system, and transcriptional regulators and various enzymes, e.g., CTP synthetase (PA3637). Among them are also NTPases PA4465, PA5028, PA3481, and FleN (PA1454), three of them displaying polar localization in bacterial cells. Overall, this work presents the spectrum of P. aeruginosa ParB partners and implicates the role of this protein in the cross-talk between chromosome segregation and other cellular processes. IMPORTANCE In Pseudomonas aeruginosa, a Gram-negative pathogen causing life-threatening infections in immunocompromised patients, the ParAB-parS system is involved in the precise separation of newly replicated bacterial chromosomes. In this work, we identified and characterized proteins interacting with partitioning protein ParB. We mapped the domain of interactions with its cognate ParA partner and showed that ParB-ParA interactions are crucial for the chromosome segregation and for proper SMC action on DNA. We also demonstrated ParB interactions with other DNA binding proteins, metabolic enzymes, and NTPases displaying polar localization in the cells. Overall, this study uncovers novel players cooperating with the chromosome partition system in P. aeruginosa, supporting its important regulatory role in the bacterial cell cycle.

Dataset Information

Molecular Anatomy of ParA-ParA and ParA-ParB Interactions during Plasmid Partitioning.

Publications

Molecular Anatomy of ParA-ParA and ParA-ParB Interactions during Plasmid Partitioning.

Similar Datasets

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