scholarly journals Insights into the effect of minor groove interactions and metal cofactors on mutagenic replication by human DNA polymerase β

2018 ◽  
Vol 475 (3) ◽  
pp. 571-585 ◽  
Author(s):  
Myong-Chul Koag ◽  
Seongmin Lee
Keyword(s):  
Dna Polymerase ◽  
Base Pair ◽  
Insertion Site ◽  
Kinetic Studies ◽  
Minor Groove ◽  
Dna Polymerase Β ◽  
Human Dna ◽  
Potential Factor ◽  
Enol Tautomer ◽  
Metal Cofactors

DNA polymerases accommodate various base-pair conformations in the event of incorrect insertions. In particular, Watson–Crick-like dG:dTTP base pair has been observed at the insertion site of human DNA polymerase β (pol β). A potential factor contributing to the diverse conformations of base-pair mismatches is minor groove interactions. To gain insights into the effect of minor groove interactions on base-pair conformations, we generated an Asn279Ala polβ mutant that cannot make minor groove contacts with an incoming nucleotide. We conducted structural and kinetic studies of Asn279Ala polβ in complex with incoming dTTP and templating dG or O6-methyl-dG. The crystal structure of the Asn279Ala polβ-G:T complex showed a wobble dG:dTTP base pair, indicating that the previously observed Watson–Crick-like dG:dTTP conformation was induced by the minor groove contact. In contrast, O6-methyl-dG, an analog of the enol tautomer of guanine, formed a Watson–Crick-like base pair with dTTP in the absence of the minor groove contact. These results suggest that the Watson–Crick-like G:T base pair at the insertion site is formed by the rare enol tautomers of G or T, whose population is increased by the minor groove hydrogen bond with Asn279. Kinetic studies showed that Asn279Ala mutation decreased dG:dTTP misincorporation rate six-fold in the presence of Mg2+ but increased the rate three-fold in the presence of Mn2+, highlighting the effect of minor groove interactions and metal ions on promutagenic replication by polβ.

scholarly journals Human DNA Polymerase ι Incorporates dCTP Opposite Template G via a G.C+ Hoogsteen Base Pair

Structure ◽  
2005 ◽  
Vol 13 (10) ◽  
pp. 1569-1577 ◽  
Author(s):  
Deepak T. Nair ◽  
Robert E. Johnson ◽  
Louise Prakash ◽  
Satya Prakash ◽  
Aneel K. Aggarwal
Keyword(s):  
Dna Polymerase ◽  
Base Pair ◽  
Human Dna ◽  
Dna Polymerase Ι

scholarly journals Base excision repair and design of small molecule inhibitors of human DNA polymerase β

2010 ◽  
Vol 67 (21) ◽  
pp. 3633-3647 ◽  
Author(s):  
Samuel H. Wilson ◽  
William A. Beard ◽  
David D. Shock ◽  
Vinod K. Batra ◽  
Nisha A. Cavanaugh ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Small Molecule ◽  
Base Excision Repair ◽  
Small Molecule Inhibitors ◽  
Excision Repair ◽  
Dna Polymerase Β ◽  
Human Dna ◽  
Base Excision

Detection and characterization of DNA polymerase activity in Toxoplasma gondii

Parasitology ◽  
1993 ◽  
Vol 107 (2) ◽  
pp. 135-139 ◽  
Author(s):  
A. Makioka ◽  
B. Stavros ◽  
J. T. Ellis ◽  
A. M. Johnson
Keyword(s):  
Toxoplasma Gondii ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Sedimentation Coefficient ◽  
Polymerase Activity ◽  
Magnesium Ions ◽  
Dna Polymerase Β ◽  
Human Dna ◽  
Approximate Molecular Weight

SUMMARYA DNA polymerase activity has been detected and characterized in crude extracts from tachzoites of Toxoplasma gondii. The enzyme has a sedimentation coefficient of 6·4 S, corresponding to an approximate molecular weight of 150000 assuming a globular shape. Like mammalian DNA polymerase α, the DNA polymerase of T. gondii was sensitive to N-ethylmaleimide and inhibited by high ionic strength. However, the enzyme activity was not inhibited by aphidicolin which is an inhibitor of mammalian DNA polymerases α, δ and ε and also cytosine-β-D-arabinofuranoside-5′-triphosphate which is an inhibitor of α polymerase. The activity was inhibited by 2′,3′-dideoxythymidine-5′-triphosphate which is an inhibitor of mammalian DNA polymerase β and γ. Magnesium ions (Mg2+) were absolutely required for activity and its optimal concentration was 6 mM. The optimum potassium (K+) concentration was 50 mM and a higher concentration of K+ markedly inhibited the activity. Activity was optimal at pH 8. Monoclonal antibodies against human DNA polymerase did not bind to DNA polymerase of T. gondii. Thus the T. gondii enzyme differs from the human enzymes and may be a useful target for the design of toxoplasmacidal drugs.

scholarly journals Thermodynamics of Human DNA Ligase I Trimerization and Association with DNA Polymerase β

1998 ◽  
Vol 273 (32) ◽  
pp. 20540-20550 ◽  
Author(s):  
Emilios K. Dimitriadis ◽  
Rajendra Prasad ◽  
Mary K. Vaske ◽  
Ling Chen ◽  
Alan E. Tomkinson ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Dna Ligase ◽  
Dna Polymerase Β ◽  
Human Dna ◽  
Dna Ligase I

scholarly journals A Facile Semisynthesis and Evaluation of Garcinoic Acid and Its Analogs for the Inhibition of Human DNA Polymerase β

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5847
Author(s):  
Satheesh Gujarathi ◽  
Maroof Khan Zafar ◽  
Xingui Liu ◽  
Robert L. Eoff ◽  
Guangrong Zheng
Keyword(s):  
Natural Product ◽  
Dna Polymerase ◽  
Activity Relationship ◽  
Synthetic Method ◽  
Valuable Insight ◽  
Dna Polymerase Β ◽  
Sar Studies ◽  
Human Dna ◽  
Structure Activity ◽  
Insight Into

Garcinoic acid has been identified as an inhibitor of DNA polymerase β (pol β). However, no structure-activity relationship (SAR) studies of garcinoic acid as a pol β inhibitor have been conducted, in part due to the lack of an efficient synthetic method for this natural product and its analogs. We developed an efficient semi-synthetic method for garcinoic acid and its analogs by starting from natural product δ-tocotrienol. Our preliminary SAR studies provided a valuable insight into future discovery of garcinoic acid-based pol β inhibitors.

scholarly journals Human DNA Polymerase ι Promotes Replication through a Ring-Closed Minor-Groove Adduct That Adopts a syn Conformation in DNA

2005 ◽  
Vol 25 (19) ◽  
pp. 8748-8754 ◽  
Author(s):  
William T. Wolfle ◽  
Robert E. Johnson ◽  
Irina G. Minko ◽  
R. Stephen Lloyd ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Minor Groove ◽  
Dna Lesions ◽  
Unsaturated Aldehyde ◽  
Cyclic Form ◽  
Human Dna ◽  
A Minor ◽  
Dna Polymerase Ι

ABSTRACT Acrolein, an α,β-unsaturated aldehyde, is generated in vivo as the end product of lipid peroxidation and from oxidation of polyamines. The reaction of acrolein with the N 2 group of guanine in DNA leads to the formation of a cyclic adduct, γ-hydroxy-1,N 2-propano-2′-deoxyguanosine (γ-HOPdG). Previously, we have shown that proficient replication through the γ-HOPdG adduct can be mediated by the sequential action of human DNA polymerases (Pols) ι and κ, in which Polι incorporates either pyrimidine opposite γ-HOPdG, but Polκ extends only from the cytosine. Since γ-HOPdG can adopt either a ring-closed cyclic form or a ring-opened form in DNA, to better understand the mechanisms that Pols ι and κ employ to promote replication through this lesion, we have examined the ability of these polymerases to replicate through the structural analogs of γ-HOPdG that are permanently either ring closed or ring opened. Our studies with these model adducts show that whereas the ring-opened form of γ-HOPdG is not inhibitory to synthesis by human Pols η, ι, or κ, only Polι is able to incorporate nucleotides opposite the ring-closed form, which is known to adopt a syn conformation in DNA. From these studies, we infer that (i) Pols η, ι, and κ have the ability to proficiently replicate through minor-groove DNA lesions that do not perturb the Watson-Crick hydrogen bonding of the template base with the incoming nucleotide, and (ii) Polι can accommodate a minor-groove-adducted template purine which adopts a syn conformation in DNA and forms a Hoogsteen base pair with the incoming nucleotide.

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