Nonspecific DNA binding by P1 ParA determines the distribution of plasmid partition and repressor activities

Abstract

The faithful segregation, or “partition,” of many low-copy number bacterial plasmids is driven by plasmid-encoded ATPases that are represented by the P1 plasmid ParA protein. ParA binds to the bacterial nucleoid via an ATP-dependent nonspecific DNA (nsDNA)-binding activity, which is essential for partition. ParA also has a site-specific DNA-binding activity to the par operator (parOP), which requires either ATP or ADP, and which is essential for it to act as a transcriptional repressor but is dispensable for partition. Here we examine how DNA binding by ParA contributes to the relative distribution of its plasmid partition and repressor activities, using a ParA with an alanine substitution at Arg351, a residue previously predicted to participate in site-specific DNA binding. In vivo, the parAR351A allele is compromised for partition, but its repressor activity is dramatically improved so that it behaves as a “super-repressor.” In vitro, ParAR351A binds and hydrolyzes ATP, and undergoes a specific conformational change required for nsDNA binding, but its nsDNA-binding activity is significantly damaged. This defect in turn significantly reduces the assembly and stability of partition complexes formed by the interaction of ParA with ParB, the centromere-binding protein, and DNA. In contrast, the R351A change shows only a mild defect in site-specific DNA binding. We conclude that the partition defect is due to altered nsDNA binding kinetics and affinity for the bacterial chromosome. Furthermore, the super-repressor phenotype is explained by an increased pool of non-nucleoid bound ParA that is competent to bind parOP and repress transcription. The faithful segregation, or “partition,” of many low-copy number bacterial plasmids is driven by plasmid-encoded ATPases that are represented by the P1 plasmid ParA protein. ParA binds to the bacterial nucleoid via an ATP-dependent nonspecific DNA (nsDNA)-binding activity, which is essential for partition. ParA also has a site-specific DNA-binding activity to the par operator (parOP), which requires either ATP or ADP, and which is essential for it to act as a transcriptional repressor but is dispensable for partition. Here we examine how DNA binding by ParA contributes to the relative distribution of its plasmid partition and repressor activities, using a ParA with an alanine substitution at Arg351, a residue previously predicted to participate in site-specific DNA binding. In vivo, the parAR351A allele is compromised for partition, but its repressor activity is dramatically improved so that it behaves as a “super-repressor.” In vitro, ParAR351A binds and hydrolyzes ATP, and undergoes a specific conformational change required for nsDNA binding, but its nsDNA-binding activity is significantly damaged. This defect in turn significantly reduces the assembly and stability of partition complexes formed by the interaction of ParA with ParB, the centromere-binding protein, and DNA. In contrast, the R351A change shows only a mild defect in site-specific DNA binding. We conclude that the partition defect is due to altered nsDNA binding kinetics and affinity for the bacterial chromosome. Furthermore, the super-repressor phenotype is explained by an increased pool of non-nucleoid bound ParA that is competent to bind parOP and repress transcription. The partition of low-copy prokaryotic plasmids typically requires a pair of proteins: a sequence-specific DNA-binding protein that recognizes the DNA partition site (the prokaryotic centromere) and an ATPase or GTPase that serves to mobilize and localize the plasmid in the cell (reviewed in Ref. 1Bouet J.-Y. Funnell B.E. Plasmid localization and partition in Enterobacteriaceae.EcoSal Plus. 2019; 8 (ESP-0003-2019)10.1128/ecosalplus.ESP-0003-2019Crossref PubMed Google Scholar). These Par systems are broadly divided into three classes, characterized by their NTPase protein and mechanism of action: Walker-type ATPases, actin-like ATPases, and tubulin-like GTPases. The Escherichia coli P1 plasmid is representative of the Walker-type ATPase family, encoding the ATPase protein ParA. The site-specific DNA-binding protein, ParB, binds to the partition site parS. A subgroup of ATPases within the Walker family, which includes P1 ParA, are also transcriptional repressors. P1 ParA acts to repress the par operon through specific binding to the parOP operator sequence (2Friedman S.A. Austin S.J. The P1 plasmid-partition system synthesizes two essential proteins from an autoregulated operon.Plasmid. 1988; 19 (3420178): 103-11210.1016/0147-619X(88)90049-2Crossref PubMed Google Scholar, 3Hayes F. Radnedge L. Davis M.A. Austin S.J. The homologous operons for P1 and P7 plasmid partition are autoregulated from dissimilar operator sites.Mol. Microbiol. 1994; PubMed Google Scholar). This by ParA is by ParB, and of the par The Walker of partition ATPases is the plasmid bacterial also and of which the are of the Walker-type These are to the ATPases that localization of the cell and a of proteins Plasmid and from Microbiol. PubMed Google Scholar, L. and of and PubMed Google Scholar, Funnell B.E. the nucleoid for partition and in Microbiol. PubMed Google Scholar, The in their Microbiol. PubMed Google Scholar). These ATPases in (the bacterial nucleoid for the for with the of their proteins and plasmid partition, complexes with ParA, of ParA the nucleoid of with of Microbiol. PubMed Google Scholar, F. requires assembly of ParA and DNA plasmid PubMed Google Scholar, and of plasmids by ParA PubMed Google Scholar, of P1 plasmids by distribution of the ATPase Microbiol. PubMed Google Scholar, Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, Funnell B.E. plasmid partition driven by protein PubMed Google Scholar, A ATPase of PubMed Google Scholar, of and plasmid PubMed Google Scholar, L. J.-Y. partition complexes within the of the PubMed Google Scholar, M.A. F. A through the nucleoid to plasmid Google Scholar). The of to the of ParA and and to a of ParA, to the that plasmid through a of a mechanism (reviewed in Ref. of PubMed Google Scholar). and of ATP in P1 ParA ParA a ATPase activity that is by and and ATP binding and are required for partition M.A. Austin S.J. of the ParA partition protein of the P1 Microbiol. PubMed Google Scholar, M.A. Radnedge L. F. Austin S.J. The P1 ParA protein and its ATPase activity a in the of plasmid to Microbiol. PubMed Google Scholar, J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar). of DNA binding by ParA are driven through binding of and DNA sequence to the is ATP for its site-specific binding activity to parOP Funnell B.E. The P1 plasmid partition protein a for ATP in site-specific DNA 1994; PubMed Google Scholar). DNA binding by ParA, is ATP F. requires assembly of ParA and DNA plasmid PubMed Google Scholar, Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, M.A. F. A through the nucleoid to plasmid Google Scholar, J.-Y. plasmid partition interaction of with Microbiol. Google Scholar, M.A. of partition protein ParA with nonspecific DNA and into DNA PubMed Google Scholar). binding ATP, P1 ParA undergoes a conformational change to which it the to bind nsDNA Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). The at which is to the of ParA the nucleoid through with The and of ParA and of complexes nsDNA has in a system by Funnell B.E. plasmid partition driven by protein PubMed Google Scholar, A ATPase of PubMed Google Scholar). a of P1 ParA, ParB, and DNA and to and in the of ATP Funnell B.E. P1 ParA, and DNA that are by the plasmid partition PubMed Google Scholar). The is its are representative of the that the of plasmid partition in of the residue has to the of the in and partition Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar, Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). A in the the conformational change from to and nsDNA binding but site-specific binding to In vivo, the change its partition activity, but a which the activity of that its repressor activity is and to that of ParA in the of These that and but the repressor of ParA, and that acts as a by to of ParA its in and partition. The of the protein sequence the Walker ATPase Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar, Funnell B.E. Plasmid partition PubMed Google Scholar). The subgroup of ATPases to which P1 sequence that the transcriptional In the of ParA to for binding to as a that P1 parOP and that of the homologous P7 plasmid system L. Davis Austin the of by the P1 and P7 plasmid partition PubMed Google Scholar). that the an that of a Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar). A of P1 bound to parOP DNA from the that two of the protein in its site-specific DNA-binding activity Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar). These the as previously predicted as as the that are from the the to which parOP affinity by Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar). in two partition ATPases the residue at in the ATP-dependent nsDNA-binding activity of ParA. A in the a nsDNA-binding defect and the of to bind to the par operator J.-Y. plasmid partition interaction of with Microbiol. Google Scholar). The partition is also compromised for nsDNA binding DNA binding is by and is essential for plasmid PubMed Google Scholar). In of we to examine the ParAR351A to in site-specific and nonspecific DNA binding, and how participate in and partition. We that ParAR351A is compromised in its partition but its repressor is and that it behaves as a that explained by altered affinity and kinetics for with the the of R351A in nsDNA binding by P1 ParA, and the of ParA in binding DNA in partition and of the P1 partition The of P1 ParA previously bound as a to DNA at which predicted that the residue a in ParA DNA binding to parOP and in Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar). In the the of are to the DNA the specific DNA that are bound by the of ParA. ParAR351A for binding to the parOP sequence in Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google Scholar). of the residue in a defect in its partition and repressor J.-Y. plasmid partition interaction of with Microbiol. Google so we an of ParAR351A to the of residue in and partition. partition in vivo, we the stability of a plasmid that but and We the of in coli to in the or of and in from a plasmid J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar). In the of and of coli with and (the In the of parAR351A and of plasmid by parAR351A is compromised in and to to F. and of a PubMed Google the of parOP in B.E. plasmid protein plasmids the 1988; PubMed Google the and which the and and of the of of in J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google in of in J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google with in in in J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google in in in in J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google in in in Funnell B.E. and of a allele of coli that the stability of plasmid PubMed Google the of parOP in with and J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google and to to in a We by the of to repress the of the parOP operator and sequence J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar). We a and which of the and of ParA is a repressor but in the of the (2Friedman S.A. Austin S.J. The P1 plasmid-partition system synthesizes two essential proteins from an autoregulated operon.Plasmid. 1988; 19 (3420178): 103-11210.1016/0147-619X(88)90049-2Crossref PubMed Google In to we that ParAR351A a and that its repressor activity to In the of by and parAR351A and so that only with the In the repressor activity of parAR351A only with for the repressor activity of parAR351A the for the activity of and the R351A allele into the of ParA that we The in that the R351A change compromised partition activity but the repressor activity of ParA. in we to the of ParAR351A to two how the R351A change P1 partition activity, and how the change the for the and a the for the in phenotype of we its to ATP binding by its ATPase activity and its to the conformational change to of which are required for partition activity Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, M.A. Radnedge L. F. Austin S.J. The P1 ParA protein and its ATPase activity a in the of plasmid to Microbiol. PubMed Google Scholar). We in ATPase activity and with or to the ATPase activity of proteins to the R351A change either the ATPase activity of ParA or the interaction with that is for of The from to has characterized through the of a in ParA, which is in to ATP binding Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). we also and ParAR351A the of ATP that ParAR351A for the The in the partition assembly that we in is the of the which requires ParA, ParB, and ATP, and by a in Funnell B.E. P1 ParA, and DNA that are by the plasmid partition PubMed Google Scholar). ParA, ParB, and DNA are and to and the is by the of a the as the and to a The the to but also the relative of ParA, ParB, and DNA Funnell B.E. P1 ParA, and DNA that are by the plasmid partition PubMed Google Scholar). we that the of ParAR351A to significantly with that of and the complexes that in which ParA complexes ParA and ParAR351A to the of or ParA and and assembly by but to a and with stability with complexes These that ParAR351A is to but the assembly and stability of complexes are significantly The ATP-dependent nsDNA-binding activity of Walker ParA ATPases is for partition and is a of the of plasmid partition that Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, of and plasmid PubMed Google Scholar, L. J.-Y. partition complexes within the of the PubMed Google Scholar, M.A. F. A through the nucleoid to plasmid Google Scholar, J.-Y. plasmid partition interaction of with Microbiol. Google Scholar, M.A. of partition protein ParA with nonspecific DNA and into DNA PubMed Google Scholar, DNA binding is by and is essential for plasmid PubMed Google Scholar, F. for a mechanism in PubMed Google Scholar). The for ATP and and the P1 assembly that the is and that the nsDNA-binding activity of ParA is also required for ParAR351A we it a defect in nsDNA binding that the assembly the we nsDNA that the and is by ParA binding Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). In ParA and DNA to a and for DNA binding by the of ATP (the from the for ATP and and in we in nsDNA binding and R351A proteins complexes with ParAR351A with we the of ParA proteins from the DNA the of nsDNA binding ParAR351A from the DNA the protein from DNA ParA protein with the nsDNA its ParAR351A with the we using the of nsDNA binding by ParAR351A significantly from that of in the with which the and kinetics the for in we to examine the with a that is to the of a in of the by and the from by the with and protein binding kinetics and of protein using a the PubMed Google Scholar, of by PubMed Google Scholar, and by Scholar). We which to examine to in a We a DNA that as a nsDNA The bound to which into ParA and ATP and binding of ParA to the DNA the in We that ParAR351A bound to a bound to The and also the two a of binding, at of ParA, the for ParAR351A of and the in the and which the DNA from with protein to with The of ParAR351A that of The nsDNA as a for for a in the the two proteins bind to The DNA binding using the and that ParAR351A binding to nsDNA is to and that the in assembly and in vitro, and partition in that and but represented the repressor of ParA Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar, Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar, J.-Y. Funnell B.E. P1 ParA with the P1 partition at and an ParA PubMed Google Scholar). the of ParA bound the ATP to parOP in ParA as which the to conformational that into the repressor and the for The that which is also a super-repressor the that bind to but activity is by in which to bind to parOP the bind We are to the and partition of ParA and in and in using in the bacterial cell are and A of ATP the of ParA in the cell into a in the the of in vivo, at parOP of we that binds to nsDNA in a a of the pool in the bacterial cell is from the nucleoid and to bind to the is of binding to a change in distribution a repressor in the of In we the that the relative the site-specific and nonspecific DNA-binding of ParA altered by the R351A in of site-specific DNA binding so ParAR351A as a we two DNA a and a that nsDNA by of the the parOP sequence for ParA binding, but a to F. Radnedge L. Davis M.A. Austin S.J. The homologous operons for P1 and P7 plasmid partition are autoregulated from dissimilar operator sites.Mol. Microbiol. 1994; PubMed Google Scholar). We to examine the binding of ParA to and and the relative of by we that DNA binding by ParA, bound to ADP, specific for parOP in and bound only to and to to Funnell B.E. M.A. for transcriptional by P1 and P7 PubMed Google we that ParAR351A only for binding to The of ParAR351A also only increased with to that of We the binding of and in the of ATP and of the parOP site is within the of the nsDNA we to binding at the specific and nonspecific sequence We that as we increased the of nsDNA the of with the DNA bound to the we binding to the nonspecific relative in parOP and nsDNA binding and In the of ATP but the of the of parOP a DNA and increased ParAR351A binding in that the relative for specific and nonspecific DNA and The of nsDNA to the the binding by and ParAR351A to parOP DNA. ParA binding to parOP ParAR351A to by nsDNA and This is by the of binding to parOP with nsDNA relative to that in the of In contrast, the binding of and ParAR351A to the nsDNA to by nsDNA and These that is from parOP by nsDNA is by the that ParAR351A behaves as a super-repressor the pool of bound in the cell is to repress from parOP the for We the of the R351A in in to ParA that are in by in their repressor in in the defect by the R351A ATP binding and the conformational at the of nsDNA binding, and the of the to previously characterized in the site are at and and repressor in Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar, Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). is a super-repressor the the to and but is at Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). its and ATPase and repressor activities, which are to by Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). the R351A defect the by and and we that the phenotype of the that as and R351A as We the in repressor activity to in using the low-copy parAR351A to that the super-repressor activity of parAR351A the repressor activity of we the system to the super-repressor of and parAR351A These two but and in their to repress in the and of by parAR351A is by the of but is for the to In we the ParAR351A protein to the of DNA binding in P1 ParA plasmid partition and that the conformational change that is for nsDNA-binding activity and partition, and to repressor Here we the for the conformational change from the nsDNA-binding activity, and examine how nsDNA binding site-specific DNA-binding ParA is a repressor of par it is by the (2Friedman S.A. Austin S.J. The P1 plasmid-partition system synthesizes two essential proteins from an autoregulated operon.Plasmid. 1988; 19 (3420178): 103-11210.1016/0147-619X(88)90049-2Crossref PubMed Google Scholar). The ParA super-repressor of by in its site as to that and to by J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar). that into the repressor the to Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). The ParAR351A protein a to at through an in DNA binding The R351A the relative affinity nsDNA and parOP the of into the and the binding to binding to parOP The is that binding to nsDNA the pool of which is competent to bind to This is by the that the R351A to a super-repressor in The of the R351A change is specific to the as the allele is to parAR351A in the The change in affinity and kinetics of ParAR351A binding to nsDNA with that of the that is of the nsDNA-binding site in ParA, with the by the in and J.-Y. plasmid partition interaction of with Microbiol. Google Scholar, DNA binding is by and is essential for plasmid PubMed Google Scholar). The also to a in the that and ParAR351A bind to previously that an of binding to DNA by in Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). of binding to nsDNA by the ParAR351A at of the binding of to nsDNA to with an in binding to and This in binding to nsDNA the protein binds to that of ParA binding the bacterial In contrast, the of nsDNA at ParA and a a binding and a of The in for nsDNA is a for the of nsDNA are to their to in or binding. it is that the R351A by ParA we that is the of in the of J.-Y. plasmid partition interaction of with Microbiol. Google Scholar, DNA binding is by and is essential for plasmid PubMed Google Scholar, F. of the partition and PubMed Google Scholar). of is to for ParA in of plasmids and L. J.-Y. partition complexes within the of the PubMed Google Scholar, M.A. F. A through the nucleoid to plasmid Google Scholar). The is that or a of ParA serves as a of ParA to plasmid in vivo, plasmid localization is at and plasmids are to from to partition L. J.-Y. partition complexes within the of the PubMed Google Scholar). ParA binding to the bacterial nucleoid is a of the mechanism of partition. In to ParA and in the which with the The of ParA from the to that are The ParA to the with and ParA is so that of and in a of ParA that is by is that the complexes many of ParB, so that and to the plasmid with the of ParA. The of ParA to as the partition with ParA the ATP is for in the and we in the P1 partition in ATP binding, ParA undergoes a conformational change to which is of binding to DNA. DNA complexes with ParA, ATP the of and ParA from the The complexes to with and the of plasmid ParAR351A to the of DNA binding the that the R351A the of ParA with ATP or its to the change to and the binding to nsDNA We conclude that defect is for the defect in assembly that the nsDNA-binding activity of ParA is to complexes in assembly by ParAR351A by the of ParA that it is also by the of ParA to with the and of the nsDNA-binding activity of ParA the and of ParA that the a affinity and of ParA ParA the nucleoid to with bound to and the plasmid with ParA the a of ParA binding kinetics change the of the ParA which the of of the nucleoid that are of ParA by The the to as as from DNA that the DNA Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar, Funnell B.E. plasmid partition driven by protein PubMed Google Scholar). for the a from which the and to and are by of which the of nsDNA binding and its the and from of the PubMed Google Scholar, L. mechanism for faithful of PubMed Google that a of ParA in the of and ParA and of and the and of The the of of the is as with the of P1 ParA acts as the for plasmid partition and the repressor of the par by nonspecific and site-specific DNA-binding activities, ParA with ATP to and The with ParAR351A the of the of DNA-binding in also in by its activity as a P1 partition the repressor activity of ParA M.A. Radnedge L. F. Austin S.J. The P1 ParA protein and its ATPase activity a in the of plasmid to Microbiol. PubMed Google and the repressor activity partition (2Friedman S.A. Austin S.J. The P1 plasmid-partition system synthesizes two essential proteins from an autoregulated operon.Plasmid. 1988; 19 (3420178): 103-11210.1016/0147-619X(88)90049-2Crossref PubMed Google Scholar, J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google two are and the The of either in or in to by ParA in of the P1 plasmid of P1 partition PubMed Google with a for in the nsDNA-binding of ParA to its site-specific DNA-binding ParA from the nucleoid partition has a to partition with the that binds and of by the 2019; PubMed Google Scholar, F. DNA proteins are 2019; PubMed Google Scholar, DNA requires in PubMed Google Scholar). Furthermore, the that which binds to the of ParB, to DNA it at and partition complexes are to partition L. mechanism for faithful of PubMed Google a of to with the of ParA the bacterial In by a of at parS. ATP by the a that is by the R351A substitution in ParA. is for and ATP for is an of and of the protein, and DNA essential to the by ParA and coli for plasmid and plasmid stability coli as for in are in in with of and is is also with and or The plasmid is it and Funnell B.E. and of a allele of coli that the stability of plasmid PubMed Google Scholar). or and in of coli and or the into with at and and with with to or to plasmid A of for and at three Plasmid as the of in the the by and of the Escherichia coli P1 by PubMed Google using and systems that previously J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar). the low-copy system a into the coli and the into the with or in the of a in the and in with at and of with for in the with three for of three P1 ParA and ParAR351A and as previously Funnell B.E. The P1 plasmid partition protein a for ATP in site-specific DNA 1994; PubMed Google Scholar, Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). ATPase activity in of and of DNA for at and by as previously J.-Y. Funnell B.E. the site of P1 partition and for ATP binding and PubMed Google Scholar, Funnell B.E. of the ATPase site of P1 ParA essential for plasmid PubMed Google Scholar). to previously Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google Scholar). in at an of and at in a at by ParA and in and for The from the ATP and the and to the for an The to that the of ATP, for of ParA, of and DNA-binding of ParA to DNA as previously Funnell B.E. ATP of P1 a for the nucleoid in plasmid Microbiol. Google and as for in at an of and at of of ATP, and ParA as in as previously Funnell B.E. P1 ParA, and DNA that are by the plasmid partition PubMed Google Scholar). in a at with and to ParA, ParB, of and of in and for ATP in with of with the and for DNA for by with and is a to the sequence of from with and is a from with and is a from which from by of the parOP sequence previously to for ParA repressor F. Radnedge L. Davis M.A. Austin S.J. The homologous operons for P1 and P7 plasmid partition are autoregulated from dissimilar operator sites.Mol. Microbiol. 1994; PubMed Google with and by by with the and by and by in for by with in for and with for at for three in in with and to a for to protein in with and to ParA binding, by of ParA in with and ParA and in The of nsDNA in either or is in the and a of by the of the of with the of with a in are within the We for of the and for the of system for with nonspecific DNA nucleoid DNA.