scholarly journals The mechanism of gap creation by a multifunctional nuclease during base excision repair

2021 ◽  
Vol 7 (29) ◽  
pp. eabg0076
Author(s):  
Jungmin Yoo ◽  
Donghun Lee ◽  
Hyeryeon Im ◽  
Sangmi Ji ◽  
Sanghoon Oh ◽  
...  
Keyword(s):  
Base Excision Repair ◽  
Single Molecule ◽  
Excision Repair ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Ap Endonuclease ◽  
Base Excision ◽  
Polymerase I ◽  
Gap Creation ◽  
Ap Site

During base excision repair, a transient single-stranded DNA (ssDNA) gap is produced at the apurinic/apyrimidinic (AP) site. Exonuclease III, capable of performing both AP endonuclease and exonuclease activity, are responsible for gap creation in bacteria. We used single-molecule fluorescence resonance energy transfer to examine the mechanism of gap creation. We found an AP site anchor-based mechanism by which the intrinsically distributive enzyme binds strongly to the AP site and becomes a processive enzyme, rapidly creating a gap and an associated transient ssDNA loop. The gap size is determined by the rigidity of the ssDNA loop and the duplex stability of the DNA and is limited to a few nucleotides to maintain genomic stability. When the 3′ end is released from the AP endonuclease, polymerase I quickly initiates DNA synthesis and fills the gap. Our work provides previously unidentified insights into how a signal of DNA damage changes the enzymatic functions.

scholarly journals DNA Breaks and Gaps Target Retroviral Integration

2021 ◽  
Author(s):  
Gayan Senavirathne ◽  
Anne Gardner ◽  
James London ◽  
Ryan K. Messer ◽  
Yow-Yong Tan ◽  
...  
Keyword(s):  
Single Molecule ◽  
Excision Repair ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Dna Breaks ◽  
Retroviral Integration ◽  
Dna Lesion ◽  
Nucleotide Insertion ◽  
Base Excision

Integration into a host genome is essential for retrovirus infection and is catalyzed by a nucleoprotein complex (Intasome) containing the virus-encoded integrase (IN) and the reverse transcribed (RT) virus copy DNA (cDNA). Previous studies suggested that integration was limited by intasome-host DNA recognition progressions. Using single molecule Forster resonance energy transfer (smFRET) we show that PFV intasomes pause at nicked and gapped DNA, which targeted site-directed integration without inducing significant intasome conformational alterations. Base excision repair (BER) components that affect retroviral integration in vivo produce similar nick/gap intermediates during DNA lesion processing. Intasome pause dynamics was modified by the 5′-nick-gap chemistry, while an 8-oxo-guanine lesion, a mismatch, or a nucleotide insertion that induce backbone flexibility and/or static bends had no effect. These results suggest that dynamic often non-productive intasome-DNA interactions may be modulated to target retroviral integration.

Studies on the base excision repair (BER) complex in Pyrococcus furiosus

2009 ◽  
Vol 37 (1) ◽  
pp. 79-82 ◽  
Author(s):  
Shinichi Kiyonari ◽  
Saki Tahara ◽  
Maiko Uchimura ◽  
Tsuyoshi Shirai ◽  
Sonoko Ishino ◽  
...  
Keyword(s):  
Base Excision Repair ◽  
Pyrococcus Furiosus ◽  
Excision Repair ◽  
Repair Process ◽  
Nuclear Antigen ◽  
Physical Interaction ◽  
Ap Endonuclease ◽  
Reading Frame ◽  
Base Excision

We have been studying the functions of PCNA (proliferating-cell nuclear antigen) for the assembly and reassembly of the replisome during replication fork progression. We have identified the functional interactions between PCNA and several proteins involved in DNA replication and repair from Pyrococcus furiosus. We recently reported that the activity of UDG (uracil–DNA glycosylase) in P. furiosus (PfuUDG) is stimulated by PCNA (PfuPCNA) in vitro, and identified an atypical PCNA-binding site, AKTLF, in the PfuUDG protein. To understand further the function of the complex in the BER (base excision repair) process, we investigated the AP (apurinic/apyrimidinic) endonuclease, which can process the BER pathway after uracil removal by UDG. Interestingly, one candidate ORF (open reading frame) for the AP endonuclease was found in the operon containing the gene encoding UDG in the P. furiosus genome. However, this ORF did not exhibit any activity. Instead, we identified the AP endonuclease activity from the other candidate gene products, and designated the protein as PfuAP. We discovered a physical interaction between PfuAP and PfuPCNA, suggesting the formation of a BER complex in one of the repair systems in P. furiosus.

scholarly journals A novel regulatory circuit in base excision repair involving AP endonuclease 1, Creb1 and DNA polymerase β

2010 ◽  
Vol 39 (8) ◽  
pp. 3156-3165 ◽  
Author(s):  
De-Sheng Pei ◽  
Xiao-Jie Yang ◽  
Wei Liu ◽  
Jeroen E. J. Guikema ◽  
Carol E. Schrader ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Base Excision Repair ◽  
Excision Repair ◽  
Dna Polymerase Β ◽  
Ap Endonuclease ◽  
Regulatory Circuit ◽  
Ap Endonuclease 1 ◽  
Base Excision

scholarly journals Spontaneous Mutagenesis Is Enhanced in Apex Heterozygous Mice

2004 ◽  
Vol 24 (18) ◽  
pp. 8145-8153 ◽  
Author(s):  
Jessica Huamani ◽  
C. Alex McMahan ◽  
Damon C. Herbert ◽  
Robert Reddick ◽  
John R. McCarrey ◽  
...  
Keyword(s):  
Base Excision Repair ◽  
Germ Line ◽  
Excision Repair ◽  
Spontaneous Mutant ◽  
Spermatogenic Cells ◽  
Ap Endonuclease ◽  
Repair Activity ◽  
Base Excision ◽  
Mutant Frequency

ABSTRACT Germ line DNA directs the development of the next generation and, as such, is profoundly different from somatic cell DNA. Spermatogenic cells obtained from young adult lacI transgenic mice display a lower spontaneous mutant frequency and greater in vitro base excision repair activity than somatic cells and tissues obtained from the same mice. However, spermatogenic cells from old lacI mice display a 10-fold higher mutant frequency. This increased spontaneous mutant frequency occurs coincidentally with decreased in vitro base excision repair activity for germ cell and testicular extracts that in turn corresponds to a decreased abundance of AP endonuclease. To directly test whether a genetic diminution of AP endonuclease results in increased spontaneous mutant frequencies in spermatogenic cell types, AP endonuclease heterozygous (Apex +/−) knockout mice were crossed with lacI transgenic mice. Spontaneous mutant frequencies were significantly elevated (approximately twofold) for liver and spleen obtained from 3-month-old Apex +/− lacI + mice compared to frequencies from Apex +/+ lacI + littermates and were additionally elevated for somatic tissues from 9-month-old mice. Spermatogenic cells from 9-month-old Apex +/− lacI + mice were significantly elevated twofold compared to levels for 9-month-old Apex +/+ lacI + control mice. These data indicate that diminution of AP endonuclease has a significant effect on spontaneous mutagenesis in somatic and germ line cells.

A Single-Molecule Atomic Force Microscopy Study of PARP1 and PARP2 Recognition of Base Excision Repair DNA Intermediates

2019 ◽  
Vol 431 (15) ◽  
pp. 2655-2673 ◽  
Author(s):  
Maria V. Sukhanova ◽  
Loic Hamon ◽  
Mikhail M. Kutuzov ◽  
Vandana Joshi ◽  
Sanae Abrakhi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Base Excision Repair ◽  
Single Molecule ◽  
Excision Repair ◽  
Microscopy Study ◽  
Atomic Force Microscopy Study ◽  
Force Microscopy ◽  
Atomic Force ◽  
Base Excision

AP endonuclease and poly(ADP-ribose) polymerase-1 interact with the same base excision repair intermediate

DNA Repair ◽  
2004 ◽  
Vol 3 (6) ◽  
pp. 581-591 ◽  
Author(s):  
Cheryl Cistulli ◽  
Olga I Lavrik ◽  
Rajendra Prasad ◽  
Esther Hou ◽  
Samuel H Wilson
Keyword(s):  
Base Excision Repair ◽  
Excision Repair ◽  
Ap Endonuclease ◽  
Base Excision

scholarly journals When UDG and hAPE1 Meet Cyclopurines. How (5′R) and (5′S) 5′,8-Cyclo-2′-deoxyadenosine and 5′,8-Cyclo-2′-deoxyguanosine Affect UDG and hAPE1 Activity?

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5177
Author(s):  
Michał Szewczuk ◽  
Karolina Boguszewska ◽  
Julia Kaźmierczak-Barańska ◽  
Bolesław T. Karwowski
Keyword(s):  
Base Excision Repair ◽  
Excision Repair ◽  
Dna Lesions ◽  
Repair System ◽  
Cellular Mechanisms ◽  
Uracil Dna Glycosylase ◽  
Base Excision ◽  
Base Excision Repair System ◽  
Synthetic Oligonucleotides ◽  
Ap Site

Ionizing radiation is a factor that seriously damages cellular mechanisms/macromolecules, e.g., by inducing damage in the human genome, such as 5′,8-cyclo-2′-deoxypurines (cdPus). CdPus may become a component of clustered DNA lesions (CDL), which are notably unfavorable for the base excision repair system (BER). In this study, the influence of 5′S and 5′R diastereomers of 5′,8-cyclo-2′-deoxyadenosine (cdA) and 5′,8-cyclo-2′-deoxyguanosine (cdG) on the uracil-DNA glycosylase (UDG) and human AP site endonuclease 1 (hAPE1) activity has been taken under consideration. Synthetic oligonucleotides containing 2′-deoxyuridine (dU) and cdPu were used as a model of single-stranded CDL. The activity of the UDG and hAPE1 enzymes decreased in the presence of RcdG compared to ScdG. Contrary to the above, ScdA reduced enzyme activity more than RcdA. The presented results show the influence of cdPus lesions located within CDL on the activity of the initial stages of BER dependently on their position toward dU. Numerous studies have shown the biological importance of cdPus (e.g., as a risk of carcinogenesis). Due to that, it is important to understand how to recognize and eliminate this type of DNA damage from the genome.

scholarly journals Probing the molecular mechanism of action of Deinococcus radiodurans RecD2 at single-molecule resolution

2021 ◽  
Author(s):  
Deb Purkait ◽  
Farhana Islam ◽  
Padmaja P. Mishra
Keyword(s):  
Single Molecule ◽  
Deinococcus Radiodurans ◽  
Excision Repair ◽  
Structural Characteristics ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Dna Unwinding ◽  
X Ray Crystallography ◽  
Domains Of Life ◽  
Molecular Mechanism Of Action

Helicases are ATP-driven molecular machines that directionally remodel nucleic acid polymers in all three domains of life. Helicases are responsible for resolving double-stranded DNA (dsDNA) into separate single-strands and this activity is essential for DNA replication, nucleotide excision repair, and homologous recombination. RecD2 from Deinococcus radiodurans (DrRecD2) has important contributions towards its unusually high tolerance to gamma radiation and hydrogen peroxide. Although previous X-ray Crystallography studies have revealed the structural characteristics of the protein, the direct experimental evidence regarding the dynamics of the DNA unwinding process by DrRecD2 in the context of other accessory proteins is yet to be found. In this study, we have probed the exact binding event and processivity of DrRecD2 at single-molecule resolution using Protein-induced fluorescence enhancement (smPIFE) and Forster resonance energy transfer (smFRET). We have found that the protein prefers to bind at the 5 prime terminal end of the single-stranded DNA (ssDNA) by Drift and has helicase activity even in absence of ATP. However, a faster and iterative mode of DNA unwinding was evident in presence of ATP. The rate of translocation of the protein was found to be slower on dsDNA compared to ssDNA. We also showed that DrRecD2 is recruited at the binding site by the single-strand binding protein (SSB) and during the unwinding, it can displace RecA from ssDNA.

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