The role of Par proteins in the active segregation of the P1 plasmid

Li, Yongfang; Dabrazhynetskaya, Alena; Youngren, Brenda; Austin, Stuart

doi:10.1111/j.1365-2958.2004.04111.x

Cited by 39 publications

(43 citation statements)

References 25 publications

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“…Studies of K122E mutant ParA from P1 showed that this substitution did not alter the protein configuration, but reduced the ATPase activity. Moreover, this protein was defective in DNA binding regardless of the presence of ATP and thus could not regulate the par operon (Davis et al, 1996;Li et al, 2004). Later, Fung et al (2001) suggested that the lysine substitution altered the the ability of ParA to bind ATP.…”

Section: Introductionmentioning

confidence: 99%

Mapping of the interactions between partition proteins Delta and Omega of plasmid pSM19035 from Streptococcus pyogenes

Dmowski

Jagura-Burdzy

2011

Microbiology

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Formation of the segrosome, a nucleoprotein complex crucial for proper functioning of plasmid partition systems, involves interactions between specific partition proteins (ParA-like and ParBlike), ATP and specific DNA sequences (the centromeric sites). Although partition systems have been studied for many years, details of the segrosome formation are not yet clear. Organization of the pSM19035-encoded partition system is unique; in contrast with other known par systems, here, the d and v genes do not constitute an operon. Moreover, Omega [a ParB-like protein which has a Ribbon-Helix-Helix (RHH) structure] recognizes multiple centromeric sequences located in the promoters of d, v and copS (copy-number control gene). The ParA-like protein Delta is a Walker-type ATPase. In this work, we identify the interaction domains and requirements for dimerization and hetero-interactions of the Delta and Omega proteins of pSM19035 plasmid. The RHH structures are involved in Omega dimerization in vivo and its N-terminal unstructured part is indispensable for association with Delta, both in vivo and in vitro. Omega does not need to form dimers to interact with Delta. ATP binding is not required for Delta dimerization but is important for interaction with Omega in vivo. The in vitro interaction between Delta and Omega depends on ATP but does not require the presence of specific DNA segments (the centromere) recognized by Omega. The C-terminal part of the Delta protein (aa 198-284) is indispensable for interaction with Omega. Delta most probably interacts with Omega as a dimer since two amino acid substitutions in a conserved region between the A9 and B motifs abolish both the dimerization of Delta and its interaction with Omega.

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Section: Introductionmentioning

confidence: 99%

Mapping of the interactions between partition proteins Delta and Omega of plasmid pSM19035 from Streptococcus pyogenes

Dmowski

Jagura-Burdzy

2011

Microbiology

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“…In common with other ParA proteins, ParF is a weak ATPase whose nucleotide hydrolysis is enhanced Ϸ30-fold by ParG (9). ATP binding and/or hydrolysis by ParA proteins has long been recognized as a crucial facet of the segregation process, although its mechanistic purpose was uncertain (10)(11)(12). We have recently shown that ATP binding stimulates the polymerization of ParF into extensive multistranded filaments, whereas ADP antagonizes filamentation.…”

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confidence: 99%

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif

Barillà

Carmelo²,

Hayes

2007

Proc. Natl. Acad. Sci. U.S.A.

115

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ParA superfamily ͉ polymerization ͉ plasmid partition ͉ ATPase T he precise distribution of newly replicated genomes to progeny cells is imperative for stable transmission of genetic information. In bacteria, the most well characterized segregation mechanisms are specified by low-copy-number plasmids. These systems most frequently comprise two plasmid-encoded proteins, often termed ParA and ParB, that assemble on a cis-acting centromeric site. ParB directly binds the centromere, whereas ParA is recruited by interactions with ParB. The resulting segrosome complex is a positioning apparatus that localizes the attached plasmids to specific subcellular addresses (1, 2).The segregation locus of multidrug-resistance plasmid TP228 in Escherichia coli consists of the parF and parG genes and nearby parH centromere (3). ParG (8.6 kDa) is the prototype of a class of small proteins involved in accurate segregation that are unrelated phylogenetically to ParB, but that fulfil analogous functions as centromere-binding factors (1,4,5). ParG is dimeric, with symmetric C-terminal domains that interleave into a ribbon-helixhelix fold that is crucial for DNA binding, and unstructured N-terminal tails (4, 6). Additional to its role as a centromerebinding protein, ParG is a transcriptional repressor of the parFG genes: transient associations between the flexible and folded domains in complex with target DNA modulate organization of a higher-order complex critical for transcriptional repression (7).The ParA superfamily of ATPases, widely encoded by both chromosomes and plasmids, is characterized by a variant Walkertype ATP-binding motif (8). ParF (22.0 kDa) epitomizes one clade of the superfamily (3). In common with other ParA proteins, ParF is a weak ATPase whose nucleotide hydrolysis is enhanced Ϸ30-fold by ParG (9). ATP binding and/or hydrolysis by ParA proteins has long been recognized as a crucial facet of the segregation process, although its mechanistic purpose was uncertain (10-12). We have recently shown that ATP binding stimulates the polymerization of ParF into extensive multistranded filaments, whereas ADP antagonizes filamentation. ParG is another key modulator of polymerization (9). Mutagenesis of the ATP-binding site in Parf perturbed DNA segregation in vivo, ATP hydrolysis, and polymerization. We envisage that segrosome formation is initiated by site-specific binding of ParG to parH, generating paired complexes of specific topology. ParF is then recruited. ParF polymerization within the complex is controlled by nucleotide binding, by ParG-mediated stimulation of ATP hydrolysis, by remodeling effects of ParG, and, more speculatively, by cell cycle signals. Polymerization, or depolymerization, invokes separation of paired plasmids and their segregation in opposite poleward directions (1, 9).Arginine fingers stimulate nucleotide hydrolysis by NTPases through the action of an arginine side chain inserted into the catalytic niche (13,14). The arginine stabilizes the transition state through neutralization of negative charge...

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“…Like similar systems found in other low-copy-number plasmids, it assures the faithful distribution of the plasmids between dividing cells by an active process akin to mitosis (10,19). The parA gene encodes a Walker-type ATPase essential for plasmid movement during partition (6,15). The parB gene encodes a protein that can bind tightly to the partition site, parS (5,8).…”

mentioning

confidence: 99%

“…The parB gene encodes a protein that can bind tightly to the partition site, parS (5,8). It is required for capture of the plasmid at the cell center prior to partition (15).…”

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confidence: 99%

Plasmid Partition System of the P1parFamily from the pWR100 Virulence Plasmid ofShigella flexneri

2005

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P1par family members promote the active segregation of a variety of plasmids and plasmid prophages in gram-negative bacteria. Each has genes for ParA and ParB proteins, followed by a parS partition site. The large virulence plasmid pWR100 of Shigella flexneri contains a new P1par family member: pWR100par. Although typical parA and parB genes are present, the putative pWR100parS site is atypical in sequence and organization. However, pWR100parS promoted accurate plasmid partition in Escherichia coli when the pWR100 Par proteins were supplied. Unique BoxB hexamer motifs within parS define species specificities among previously described family members. Although substantially different from P1parS from the P1 plasmid prophage of E. coli, pWR100parS has the same BoxB sequence. As predicted, the species specificity of the two types proved identical. They also shared partition-mediated incompatibility, consistent with the proposed mechanistic link between incompatibility and species specificity. Among several informative sequence differences between pWR100parS and P1parS is the presence of a 21-bp insert at the center of the pWR100parS site. Deletion of this insert left much of the parS activity intact. Tolerance of central inserts with integral numbers of helical DNA turns reflects the critical topology of these sites, which are bent by binding the host IHF protein.

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The role of Par proteins in the active segregation of the P1 plasmid

Cited by 39 publications

References 25 publications

Mapping of the interactions between partition proteins Delta and Omega of plasmid pSM19035 from Streptococcus pyogenes

Mapping of the interactions between partition proteins Delta and Omega of plasmid pSM19035 from Streptococcus pyogenes

The tail of the ParG DNA segregation protein remodels ParF polymers and enhances ATP hydrolysis via an arginine finger-like motif

Plasmid Partition System of the P1parFamily from the pWR100 Virulence Plasmid ofShigella flexneri

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