The reactivation of DnaA(L366K) requires less acidic phospholipids supporting their role in the initiation of chromosome replication in <i>Escherichia coli</i>

Aranovich, Alexander; Parola, Abraham H.; Fishov, Itzhak

doi:10.1016/j.febslet.2007.08.019

Cited by 10 publications

(11 citation statements)

References 28 publications

(54 reference statements)

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“…We consider DnaA-membrane binding as a mediator of the functional state of bacteria, specifically, growth rate; this may help explain the enigmatic ‘initiation mass’ [62]–[64]. Indeed, we have suggested previously that the ‘initiation mass’ may result from the phenomenon of a highly cooperative inter-conversion between two functional states of DnaA driven by its membrane surface occupancy [34], [36]. Our present results provide a strong basis for extrapolation of this phenomenon to in vivo situation.…”

Section: Discussionmentioning

confidence: 99%

“…The switching role of DnaA-membrane binding was supported by a cooperative transition in nucleotide binding affinity driven by DnaA density on the membrane surface [34]. Moreover, DnaA mutant L366K, which rescued an acidic phospholipid-deficient strain from growth arrest [35], required less phospholipids for its activation [36]. These findings, together with the concept of membrane domains [37], [38], suggest the nature of the mechanism responsible for transducing continuous cell growth into DnaA activity switch at the appropriate time in the cell cycle.…”

Section: Introductionmentioning

confidence: 99%

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Association of the Chromosome Replication Initiator DnaA with the Escherichia coli Inner Membrane In Vivo: Quantity and Mode of Binding

et al. 2012

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DnaA initiates chromosome replication in most known bacteria and its activity is controlled so that this event occurs only once every cell division cycle. ATP in the active ATP-DnaA is hydrolyzed after initiation and the resulting ADP is replaced with ATP on the verge of the next initiation. Two putative recycling mechanisms depend on the binding of DnaA either to the membrane or to specific chromosomal sites, promoting nucleotide dissociation. While there is no doubt that DnaA interacts with artificial membranes in vitro, it is still controversial as to whether it binds the cytoplasmic membrane in vivo. In this work we looked for DnaA-membrane interaction in E. coli cells by employing cell fractionation with both native and fluorescent DnaA hybrids. We show that about 10% of cellular DnaA is reproducibly membrane-associated. This small fraction might be physiologically significant and represent the free DnaA available for initiation, rather than the vast majority bound to the datA reservoir. Using the combination of mCherry with a variety of DnaA fragments, we demonstrate that the membrane binding function is delocalized on the surface of the protein’s domain III, rather than confined to a particular sequence. We propose a new binding-bending mechanism to explain the membrane-induced nucleotide release from DnaA. This mechanism would be fundamental to the initiation of replication.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Association of the Chromosome Replication Initiator DnaA with the Escherichia coli Inner Membrane In Vivo: Quantity and Mode of Binding

et al. 2012

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“…However, findings from a study that used an ATP fluorescent analog, 2′-(or-3′)- O -( N -methylanthraniloyl) adenosine 5′ tri-phosphate (MANT-ATP), suggest that DnaA(L366K) might require a lower concentration of acidic phospholipids to induce the exchange of ADP to ATP bound to DnaA protein [74]. This study postulates that the low levels of PG and CL arising from repressed pgsA expression may be sufficient for promoting ADP-ATP exchange on DnaA(L366K), but not wild-type DnaA.…”

Section: Linkage Between Bacterial Growth and Membrane Acidic Phosmentioning

confidence: 99%

Crosstalk between DnaA Protein, the Initiator of Escherichia coli Chromosomal Replication, and Acidic Phospholipids Present in Bacterial Membranes

Saxena

Fingland

Patil

et al. 2013

IJMS

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Anionic (i.e., acidic) phospholipids such as phosphotidylglycerol (PG) and cardiolipin (CL), participate in several cellular functions. Here we review intriguing in vitro and in vivo evidence that suggest emergent roles for acidic phospholipids in regulating DnaA protein-mediated initiation of Escherichia coli chromosomal replication. In vitro acidic phospholipids in a fluid bilayer promote the conversion of inactive ADP-DnaA to replicatively proficient ATP-DnaA, yet both PG and CL also can inhibit the DNA-binding activity of DnaA protein. We discuss how cellular acidic phospholipids may positively and negatively influence the initiation activity of DnaA protein to help assure chromosomal replication occurs once, but only once, per cell-cycle. Fluorescence microscopy has revealed that PG and CL exist in domains located at the cell poles and mid-cell, and several studies link membrane curvature with sub-cellular localization of various integral and peripheral membrane proteins. E. coli DnaA itself is found at the cell membrane and forms helical structures along the longitudinal axis of the cell. We propose that there is cross-talk between acidic phospholipids in the bacterial membrane and DnaA protein as a means to help control the spatial and temporal regulation of chromosomal replication in bacteria.

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“…DnaAL366K) (270), although the mechanism for the suppression is not yet clear. It is also suggested that a high local DnaA concentration in the membrane may be necessary to regulate ADP to ATP exchange (3). …”

Section: Factors Involved In Initiation Of Chromosome Replicationmentioning

confidence: 99%

Initiation of DNA Replication

Leonard

Grimwade

2010

EcoSal Plus

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In recent years it has become clear that complex regulatory circuits control the initiation step of DNA replication by directing the assembly of a multicomponent molecular machine (the orisome) that separates DNA strands and loads replicative helicase at oriC , the unique chromosomal origin of replication. This chapter discusses recent efforts to understand the regulated protein-DNA interactions that are responsible for properly timed initiation of chromosome replication. It reviews information about newly identified nucleotide sequence features within Escherichia coli oriC and the new structural and biochemical attributes of the bacterial initiator protein DnaA. It also discusses the coordinated mechanisms that prevent improperly timed DNA replication. Identification of the genes that encoded the initiators came from studies on temperature-sensitive, conditional-lethal mutants of E. coli , in which two DNA replication-defective phenotypes, "immediate stop" mutants and "delayed stop" mutants, were identified. The kinetics of the delayed stop mutants suggested that the defective gene products were required specifically for the initiation step of DNA synthesis, and subsequently, two genes, dnaA and dnaC , were identified. The DnaA protein is the bacterial initiator, and in E. coli , the DnaC protein is required to load replicative helicase. Regulation of DnaA accessibility to oriC , the ordered assembly and disassembly of a multi-DnaA complex at oriC , and the means by which DnaA unwinds oriC remain important questions to be answered and the chapter discusses the current state of knowledge on these topics.

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The reactivation of DnaA(L366K) requires less acidic phospholipids supporting their role in the initiation of chromosome replication in Escherichia coli

Cited by 10 publications

References 28 publications

Association of the Chromosome Replication Initiator DnaA with the Escherichia coli Inner Membrane In Vivo: Quantity and Mode of Binding

Association of the Chromosome Replication Initiator DnaA with the Escherichia coli Inner Membrane In Vivo: Quantity and Mode of Binding

Crosstalk between DnaA Protein, the Initiator of Escherichia coli Chromosomal Replication, and Acidic Phospholipids Present in Bacterial Membranes

Initiation of DNA Replication

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