scholarly journals The Escherichia coli Fis protein prevents initiation of DNA replication from oriC in vitro

1996 ◽  
Vol 24 (18) ◽  
pp. 3527-3532 ◽  
Author(s):  
S Wold
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Initiation Of Dna Replication

The Escherichia coli chaperones involved in DNA replicadon

1993 ◽  
Vol 339 (1289) ◽  
pp. 271-278 ◽  
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Conformational Changes ◽  
Heat Shock Genes ◽  
Dnab Helicase ◽  
Initiation Of Dna Replication ◽  
Shock Proteins

Mutadons in the Escherichia coli heat shock genes, dnaK , dnaJ or grpE , alter host DNA and RNA synthesis, degradation of other proteins, cell division and expression of other heat shock genes. They also block the initiation of DNA replication of bacteriophages λ and P1, and the mini-F plasmid. An in vitro λDNA replication system, composed entirely of purified components, enabled us to describe the molecular mechanism of the dnaK , dnaJ and grpE gene products. DnaK , the bacterial hsp 70 homologue, releases λP protein from the preprimosomal complex in an ATP- and DnaJ-dependent reaction (GrpEindependent initiation of λDNA replication). In this paper, I show that, when GrpE is present, λP protein is not released from the preprimosomal complex, rather it is translocated within the complex in such a way that it does not inhibit DnaB helicase activity. Translocation of λP triggers the initiation event allowing DnaB helicase to unwind DNA near the ori λ sequence, leading to efficient λDNA replication. Chaperone activity of the DnaK -DnaJ-GrpE system is first manifested in the selective binding of these heat shock proteins to the preprimosomal complex, followed by its ATP-dependent rearrangement. I show that DnaJ not only tags the preprimosomal complex for recognition by DnaK, but also stabilizes the multi-protein structure. GrpE also participates in the binding of DnaK to the preprimosomal complex by increasing DnaK ’s affinity to those λP proteins which are already associated with DnaJ. After attracting DnaK to the preprimosomal complex, DnaJ and GrpE stimulate the ATPase activity of DnaK , triggering conformational changes in DnaK which are responsible for the rearrangement of proteins in the preprimosomal complex and recycling of these heat shock proteins. The role of DnaK , DnaJ and GrpE in λDNA replication is in sharp contrast to our understanding of their role in the oriC , P1, and probably mini-F DNA replication systems. In the cases of oriC and P1 DNA replication, these heat shock proteins activate initiation factors before they are in contact with DNA, and are not required during the subsequent steps leading to the initiation of DNA replication. The common feature of DnaK , DnaJ and GrpE action in these systems is their ATP-dependent disaggregation or rearrangement of protein complexes formed before or during initiation of DNA replication.

scholarly journals Termination complex in Escherichia coli inhibits SV40 DNA replication in vitro by impeding the action of T antigen helicase.

1992 ◽  
Vol 267 (8) ◽  
pp. 5361-5365
Author(s):  
M Hidaka ◽  
T Kobayashi ◽  
Y Ishimi ◽  
M Seki ◽  
T Enomoto ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
T Antigen ◽  
Sv40 Dna

scholarly journals Differential Suppression of priA2::kan Phenotypes in Escherichia coli K-12 by Mutations in priA, lexA, and dnaC

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Steven J Sandler ◽  
Hardeep S Samra ◽  
Alvin J Clark
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Mutant Allele ◽  
Wild Type ◽  
Suppressor Mutations ◽  
Dnab Helicase ◽  
K 12 ◽  
Extragenic Suppressors ◽  
Assembly Activity

Abstract First identified as an essential component of the ϕX174 in vitro DNA replication system, PriA has ATPase, helicase, translocase, and primosome-assembly activities. priA1::kan strains of Escherichia coli are sensitive to UV irradiation, deficient in homologous recombination following transduction, and filamentous. priA2::kan strains have eightfold higher levels of uninduced SOS expression than wild type. We show that (1) priA1::kan strains have eightfold higher levels of uninduced SOS expression, (2) priA2::kan strains are UVS and Rec−, (3) lexA3 suppresses the high basal levels of SOS expression of a priA2::kan strain, and (4) plasmid-encoded priA300 (K230R), a mutant allele retaining only the primosome-assembly activity of priA+, restores both UVR and Rec+ phenotypes to a priA2::kan strain. Finally, we have isolated 17 independent UVR Rec+ revertants of priA2::kan strains that carry extragenic suppressors. All 17 map in the C-terminal half of the dnaC gene. DnaC loads the DnaB helicase onto DNA as a prelude for primosome assembly and DNA replication. We conclude that priA's primosome-assembly activity is essential for DNA repair and recombination and that the dnaC suppressor mutations allow these processes to occur in the absence of priA.

scholarly journals Role of Papillomavirus E1 Initiator Dimerization in DNA Replication

2005 ◽  
Vol 79 (13) ◽  
pp. 8661-8664 ◽  
Author(s):  
Stephen Schuck ◽  
Arne Stenlund
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Severe Effect ◽  
Origin Of Dna Replication ◽  
Initiation Of Dna Replication

ABSTRACT Viral initiator proteins are polypeptides that form oligomeric complexes on the origin of DNA replication (ori). These complexes carry out a multitude of functions related to initiation of DNA replication, and although many of these functions have been characterized biochemically, little is understood about how the complexes are assembled. Here we demonstrate that loss of one particular interaction, the dimerization between E1 DNA binding domains, has a severe effect on DNA replication in vivo but has surprisingly modest effects on most individual biochemical activities in vitro. We conclude that the dimer interaction is primarily required for initial recognition of ori.

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