<b>The P1 ParA protein and its ATPase activity play a direct role in the segregation of plasmid copies to daughter cells</b>

Davis, Michael A.; Radnedge, Lyndsay; Martin, K.; Hayes, Finbarr; Youngren, Brenda; Austin, Stuart

doi:10.1046/j.1365-2958.1996.721423.x

Cited by 82 publications

(86 citation statements)

References 19 publications

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“…Nucleotide binding experiments (Fig. 1) suggest one ATP binding site per ParA monomer, which agrees well with the presence of one putative ATP binding site defined by sequence analysis (10), and the observation that deletion of this region of the protein destroys ATPase activity (7). We have used different adenine nucleotide cofactors to probe the structure and function of ParA.…”

Section: Atp and Adp Binding Bysupporting

confidence: 82%

“…(Fig. 1) and hydrolyzes ATP (8), and one or both of these activities are essential for both its regulation and partition activities (7). Nucleotide binding experiments (Fig.…”

Section: Atp and Adp Binding Bymentioning

confidence: 99%

“…Roles of ATP in par Gene Regulation and Partition-The ATP site in ParA is essential for both ParA's regulation and partition activities in vivo (7). One role of ATP binding is to promote ParA binding to parOP for ParA repressor activity (8,14).…”

Section: Atp and Adp Binding Bymentioning

confidence: 99%

“…ParA repressor activity is stimulated by ParB; however, ParB has no effect on par gene expression on its own. A second role for ParA in partition is inferred from genetic data that show a requirement for ParA in partition even when its regulatory role is bypassed (6,7). Therefore, we consider ParA's repressor activity its "regulatory" function, and this second, as yet undefined role as ParA's "partition" function because we think it reflects a direct role for ParA in the positioning reaction.…”

mentioning

confidence: 99%

“…Mutation of the ParA nucleotide binding motif A interferes with both ParA repressor and partition functions in vivo (7). However, the steps at which ATP binding and hydrolysis modulate ParA function are not understood.…”

mentioning

confidence: 99%

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Modulation of the P1 Plasmid Partition Protein ParA by ATP, ADP, and P1 ParB

Davey

Funnell

1997

Journal of Biological Chemistry

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ParA is an essential P1 plasmid partition protein. It represses transcription of the par genes (parA and parB) and is also required for a second, as yet undefined step in partition. ParA is a ParB-stimulated ATPase that binds to a specific DNA site in the par promoter region. ParA is an essential component of the P1 plasmid partition system (1). The prophage of bacteriophage P1 exists as an autonomously replicating plasmid, and its copy number is about the same as that of the bacterial chromosome (2). The P1 partition system, Par, directs proper segregation and thus stable maintenance of the plasmid. The mechanism of partition is unknown, but can be thought of as a positioning process that via interaction with the Escherichia coli host ensures proper distribution of the plasmid. Par encodes two essential transacting proteins, ParA and ParB, and contains a cis-acting DNA site called parS (1). In addition, the E. coli integration host factor, IHF, 1 also participates, although it is not absolutely required (3). ParB and IHF bind to parS to form the partition complex (3-5). Assembly of this complex is assumed to be an early step in the partition pathway. Formation of this complex does not require the action of ParA (3-5), and we infer that ParA acts during a later step in the partition process.ParA has at least two roles in partition. First, ParA represses transcription of its own gene and parB from a promoter upstream of parA (6). ParA repressor activity is stimulated by ParB; however, ParB has no effect on par gene expression on its own. A second role for ParA in partition is inferred from genetic data that show a requirement for ParA in partition even when its regulatory role is bypassed (6, 7). Therefore, we consider ParA's repressor activity its "regulatory" function, and this second, as yet undefined role as ParA's "partition" function because we think it reflects a direct role for ParA in the positioning reaction. The latter function requires that ParA interact, directly or indirectly, with the ParB-IHF-parS partition complex.ParA is an ATPase and a site-specific DNA-binding protein (8). The ATPase is stimulated by ParB and nonspecific DNA (8). ParA is one of the better characterized proteins in a superfamily of ATPases defined by a modified Walker type A motif in the protein sequence (9 -11). This superfamily includes other plasmid partition proteins such as F SopA, as well as plasmid and chromosomally encoded proteins from various bacteria species whose functions have not yet been determined (10 -12). Many of the plasmids and bacterial chromosomes also encode a ParB homolog adjacent to the ParA homolog. The similarities of these ParA-like proteins with P1 ParA and F SopA have led to the suggestion that these homologs are also involved in plasmid or chromosome segregation (10, 11).ParA binds to the par promoter region called parOP (8), and this binding is thought to mediate ParA repressor activity in vivo. The recognition site for ParA is likely a large inverted repeat in the par promoter region, since (i) ...

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Section: Atp and Adp Binding Bysupporting

confidence: 82%

“…(Fig. 1) and hydrolyzes ATP (8), and one or both of these activities are essential for both its regulation and partition activities (7). Nucleotide binding experiments (Fig.…”

Section: Atp and Adp Binding Bymentioning

confidence: 99%