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

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 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

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 Nuclear Magnetic Resonance Solution Structure of the Escherichia coli DNA Polymerase III θ Subunit

2005 ◽  
Vol 187 (20) ◽  
pp. 7081-7089 ◽  
Author(s):  
Geoffrey A. Mueller ◽  
Thomas W. Kirby ◽  
Eugene F. DeRose ◽  
Dawei Li ◽  
Roel M. Schaaper ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dna Polymerase ◽  
Solution Structure ◽  
Conformational Exchange ◽  
Dna Polymerase Iii ◽  
Catalytic Core ◽  
Polymerase Iii ◽  
Nuclear Magnetic

ABSTRACT The catalytic core of Escherichia coli DNA polymerase III holoenzyme contains three subunits: α, ε, and θ. The α subunit contains the polymerase, and the ε subunit contains the exonucleolytic proofreading function. The small (8-kDa) θ subunit binds only to ε. Its function is not well understood, although it was shown to exert a small stabilizing effect on the ε proofreading function. In order to help elucidate its function, we undertook a determination of its solution structure. In aqueous solution, θ yielded poor-quality nuclear magnetic resonance spectra, presumably due to conformational exchange and/or protein aggregation. Based on our recently determined structure of the θ homolog from bacteriophage P1, named HOT, we constructed a homology model of θ. This model suggested that the unfavorable behavior of θ might arise from exposed hydrophobic residues, particularly toward the end of α-helix 3. In gel filtration studies, θ elutes later than expected, indicating that aggregation is potentially responsible for these problems. To address this issue, we recorded 1H-15N heteronuclear single quantum correlation (HSQC) spectra in water-alcohol mixed solvents and observed substantially improved dispersion and uniformity of peak intensities, facilitating a structural determination under these conditions. The structure of θ in 60/40 (vol/vol) water-methanol is similar to that of HOT but differs significantly from a previously reported θ structure. The new θ structure is expected to provide additional insight into its physiological role and its effect on the ε proofreading subunit.

scholarly journals NMR solution structure of the θ subunit of DNA polymerase III from Escherichia coli

2008 ◽  
Vol 9 (4) ◽  
pp. 721-733 ◽  
Author(s):  
Max A. Keniry ◽  
Hilary A. Berthon ◽  
Ji Yeon Yang ◽  
Caroline S. Miles ◽  
Nicholas E. Dixon
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Solution Structure ◽  
Dna Polymerase Iii ◽  
Nmr Solution Structure ◽  
Polymerase Iii

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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