Molecular assessment of S1 endonuclease-resistant snapback hairpin loops generated by DNA polymerase I during the in-vitro nick translation reaction

1985 ◽  
Vol 11 (1) ◽  
pp. 1-15
Author(s):  
Michael V. Norgard
2018 ◽  
Author(s):  
Amit Bhardwaj ◽  
Debarghya Ghose ◽  
Krishan Gopal Thakur ◽  
Dipak Dutta

AbstractThe nick translation property of DNA polymerase I (Pol I) ensures the maturation of Okazaki fragments by removing primer RNAs and facilitating ligation. However, prolonged nick translation traversing downstream DNA is an energy wasting futile process, as Pol I simultaneously polymerizes and depolymerizes at the nick sites utilizing energy-rich dNTPs. Using an in vitro assay system, we demonstrate that the β-clamp of the Escherichia coli replisome strongly inhibits nick translation on the DNA substrate. To do so, β-clamp inhibits the strand displacement activity of Pol I by interfering with the interaction between the finger subdomain of Pol I and the downstream primer-template junction. Conversely, β-clamp stimulates the 5’ exonuclease property of Pol I to cleave single nucleotides or shorter oligonucleotide flaps. This single nucleotide flap removal at high frequency increases the probability of ligation between the upstream and downstream DNA strands at an early phase, terminating nick translation. Besides β-clamp-mediated ligation helps DNA ligase to seal the nick promptly during the maturation of Okazaki fragments.


DNA Repair ◽  
2018 ◽  
Vol 64 ◽  
pp. 59-67 ◽  
Author(s):  
Kang-Yi Su ◽  
Liang-In Lin ◽  
Steven D. Goodman ◽  
Rong-Syuan Yen ◽  
Cho-Yuan Wu ◽  
...  

1986 ◽  
Vol 161 (2) ◽  
pp. 435-440 ◽  
Author(s):  
Gianfranco BADARACCO ◽  
Paola VALSASNINI ◽  
Marco FOIANI ◽  
Roberta BENFANTE ◽  
Giovanna LUCCHINI ◽  
...  

2006 ◽  
Vol 345 (3) ◽  
pp. 1083-1091 ◽  
Author(s):  
Xipeng Liu ◽  
Jingli Hou ◽  
Jianhua Liu

1982 ◽  
Vol 3 (2) ◽  
pp. 151-153 ◽  
Author(s):  
R. Balachandran ◽  
A. Srinivasan

1994 ◽  
Vol 41 (1) ◽  
pp. 79-86 ◽  
Author(s):  
S Sen ◽  
S Mukhopadhyay ◽  
J Wetzel ◽  
T K Biswas

The mitochondrial DNA (mtDNA) polymerase was isolated from a protease-deficient yeast strain (PY2), and purified about 3000 fold by a column chromatography on phosphocellulose, heparin-agarose, and single-stranded DNA cellulose. The purified polymerase was characterized with respect to optimal nucleotide concentrations, template-primer specificity and sensitivity to some inhibitors. These results were compared with the nuclear DNA polymerase I activity. Both polymerases showed similar requirement of deoxynucleotide concentrations (Km < 1 microM), and highest activity with poly(dA-dT) template. However, the mtDNA polymerase was more sensitive to ddTTP, EtBr and Mn2+ inhibition in comparison to the nuclear DNA polymerase I. The mtDNA polymerase did not need ATP as an energy source for in vitro DNA synthesis. This mtDNA polymerase preparation also showed 3'-->5' exonuclease activity.


1980 ◽  
Vol 186 (1) ◽  
pp. 325-329 ◽  
Author(s):  
S Palit ◽  
B B Goswami ◽  
D K Dube

Nitrofurantoin (1-([(5-nitrofuran-2-yl)methylene]amino)imidazolidine-2,4-dione), a widely used drug and also a well-known bacterial mutagen, inhibits DNA synthesis in mitochondria from 48 h etiolated seedlings of Vigna sinensis (Linn.) Savi (snake bean). The effect appears at the level of the uptake of radioactive deoxynucleoside triphosphates by the plant mitochondria. Nitrofurantoin does not inhibit DNA synthesis in vitro by homogeneous Escherichia coli DNA polymerase I and DNA polymerase from avian-myeloblastosis virus. No specific nitroreductase activity could be detected in mitochondria.


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