scholarly journals The unstructured C-terminus of the τ subunit of Escherichia coli DNA polymerase III holoenzyme is the site of interaction with the α subunit

2007 ◽  
Vol 35 (9) ◽  
pp. 2813-2824 ◽  
Author(s):  
Slobodan Jergic ◽  
Kiyoshi Ozawa ◽  
Neal K. Williams ◽  
Xun-Cheng Su ◽  
Daniel D. Scott ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Dna Polymerase Iii ◽  
Α Subunit ◽  
Polymerase Iii ◽  
C Terminus

Polymerases and UV mutagenesis in Escherichia coli

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 572-577 ◽  
Author(s):  
B. A. Bridges ◽  
Helen Bates ◽  
Firdaus Sharif
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Nucleic Acid ◽  
Gene Product ◽  
Ultraviolet Light ◽  
Dna Polymerase ◽  
Dna Polymerase Iii ◽  
Uv Mutagenesis ◽  
Α Subunit ◽  
Polymerase Iii

Evidence for and against the involvement of the known nucleic acid polymerases in UV mutagenesis in Escherichia coli is reviewed. There is no evidence that rules out the participation of any of them when they are present but only one, the α subunit of DNA polymerase III holoenzyme (polC gene product) has been shown to be essential. It is argued that the PolC protein that functions in UV mutagenesis may not be immediately recognizable as one of the normal cellular polymerases or polymerase complexes.Key words: polymerases, ultraviolet light, mutagenesis, DNA repair, misincorporation.

scholarly journals The θ Subunit of Escherichia coli DNA Polymerase III: a Role in Stabilizing the ε Proofreading Subunit

2004 ◽  
Vol 186 (9) ◽  
pp. 2774-2780 ◽  
Author(s):  
Sharon A. Taft-Benz ◽  
Roel M. Schaaper
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Normal Cell ◽  
Mutation Rates ◽  
Dna Polymerase Iii ◽  
Α Subunit ◽  
Polymerase Iii ◽  
Separate Protein ◽  
Gram Negative Organisms

ABSTRACT The function of the θ subunit of Escherichia coli DNA polymerase III holoenzyme is not well established. θ is a tightly bound component of the DNA polymerase III core, which contains the α subunit (polymerase), the ε subunit (3′→5′ exonuclease), and the θ subunit, in the linear order α-ε-θ. Previous studies have shown that the θ subunit is not essential, as strains carrying a deletion of the holE gene (which encodes θ) proved fully viable. No significant phenotypic effects of the holE deletion could be detected, as the strain displayed normal cell health, morphology, and mutation rates. On the other hand, in vitro experiments have indicated the efficiency of the 3′-exonuclease activity of ε to be modestly enhanced by the presence of θ. Here, we report a series of genetic experiments that suggest that θ has a stabilizing role for the ε proofreading subunit. The observations include (i) defined ΔholE mutator effects in mismatch-repair-defective mutL backgrounds, (ii) strong ΔholE mutator effects in certain proofreading-impaired dnaQ strains, and (iii) yeast two- and three-hybrid experiments demonstrating enhancement of α-ε interactions by the presence of θ. θ appears conserved among gram-negative organisms which have an exonuclease subunit that exists as a separate protein (i.e., not part of the polymerase polypeptide), and the presence of θ might be uniquely beneficial in those instances where the proofreading 3′-exonuclease is not part of the polymerase polypeptide.

scholarly journals Solution structure of Domains IVa and V of the τ subunit of Escherichia coli DNA polymerase III and interaction with the α subunit

2007 ◽  
Vol 35 (9) ◽  
pp. 2825-2832 ◽  
Author(s):  
Xun-Cheng Su ◽  
Slobodan Jergic ◽  
Max A. Keniry ◽  
Nicholas E. Dixon ◽  
Gottfried Otting
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Solution Structure ◽  
Dna Polymerase Iii ◽  
Α Subunit ◽  
Polymerase Iii

scholarly journals E. coli primase and DNA polymerase III holoenzyme are able to bind concurrently to a primed template during DNA replication

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea Bogutzki ◽  
Natalie Naue ◽  
Lidia Litz ◽  
Andreas Pich ◽  
Ute Curth
Keyword(s):  
Dna Replication ◽  
Dna Polymerase ◽  
Protein Interactions ◽  
Dna Polymerase Iii ◽  
Protein Protein Interactions ◽  
Single Stranded Dna ◽  
E Coli ◽  
Polymerase Iii ◽  
C Terminus ◽  
Pol Iii

Abstract During DNA replication in E. coli, a switch between DnaG primase and DNA polymerase III holoenzyme (pol III) activities has to occur every time when the synthesis of a new Okazaki fragment starts. As both primase and the χ subunit of pol III interact with the highly conserved C-terminus of single-stranded DNA-binding protein (SSB), it had been proposed that the binding of both proteins to SSB is mutually exclusive. Using a replication system containing the origin of replication of the single-stranded DNA phage G4 (G4ori) saturated with SSB, we tested whether DnaG and pol III can bind concurrently to the primed template. We found that the addition of pol III does not lead to a displacement of primase, but to the formation of higher complexes. Even pol III-mediated primer elongation by one or several DNA nucleotides does not result in the dissociation of DnaG. About 10 nucleotides have to be added in order to displace one of the two primase molecules bound to SSB-saturated G4ori. The concurrent binding of primase and pol III is highly plausible, since even the SSB tetramer situated directly next to the 3′-terminus of the primer provides four C-termini for protein-protein interactions.

scholarly journals The interaction of DNA polymerase III and the product of the Escherichia coli mutator gene, mutD.

1984 ◽  
Vol 259 (9) ◽  
pp. 5567-5573
Author(s):  
R DiFrancesco ◽  
S K Bhatnagar ◽  
A Brown ◽  
M J Bessman
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Dna Polymerase Iii ◽  
Mutator Gene ◽  
Polymerase Iii
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