Role of charge transfer states into the formation of cyclobutane pyrimidine dimers in DNA

2019 ◽  
Vol 216 ◽  
pp. 507-519 ◽  
Author(s):  
Wook Lee ◽  
Spiridoula Matsika
Keyword(s):  
Charge Transfer ◽  
Cyclobutane Pyrimidine Dimers ◽  
Pyrimidine Dimers

Sequence affects the energetics and role of charge transfer in oligonucleotides.

scholarly journals A Role for Histone H2B During Repair of UV-Induced DNA Damage in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1375-1387
Author(s):  
Emmanuelle M D Martini ◽  
Scott Keeney ◽  
Mary Ann Osley
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Chromatin Structure ◽  
Specific Effect ◽  
Cell Killing ◽  
Cyclobutane Pyrimidine Dimers ◽  
Histone H2b ◽  
Uv Sensitivity ◽  
Pyrimidine Dimers

Abstract To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Δ and rad52Δ mutants but not in rad6Δ or rad18Δ mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Δ) or error-free (rad30Δ) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Δ mutation. When combined with a ubc13Δ mutation, which is also epistatic with rad5Δ, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR.

scholarly journals The major mechanism of melanoma mutations is based on deamination of cytosine in pyrimidine dimers as determined by circle damage sequencing

2021 ◽  
Vol 7 (31) ◽  
pp. eabi6508
Author(s):  
Seung-Gi Jin ◽  
Dean Pettinga ◽  
Jennifer Johnson ◽  
Peipei Li ◽  
Gerd P. Pfeifer
Keyword(s):  
Sequence Specificity ◽  
Uvb Radiation ◽  
Cyclobutane Pyrimidine Dimers ◽  
Sequence Context ◽  
Cytosine Deamination ◽  
Transcription Start Sites ◽  
Major Mechanism ◽  
Pyrimidine Dimers ◽  
Genome Wide

Sunlight-associated melanomas carry a unique C-to-T mutation signature. UVB radiation induces cyclobutane pyrimidine dimers (CPDs) as the major form of DNA damage, but the mechanism of how CPDs cause mutations is unclear. To map CPDs at single-base resolution genome wide, we developed the circle damage sequencing (circle-damage-seq) method. In human cells, CPDs form preferentially in a tetranucleotide sequence context (5′-Py-T<>Py-T/A), but this alone does not explain the tumor mutation patterns. To test whether mutations arise at CPDs by cytosine deamination, we specifically mapped UVB-induced cytosine-deaminated CPDs. Transcription start sites (TSSs) were protected from CPDs and deaminated CPDs, but both lesions were enriched immediately upstream of the TSS, suggesting a mutation-promoting role of bound transcription factors. Most importantly, the genomic dinucleotide and trinucleotide sequence specificity of deaminated CPDs matched the prominent mutation signature of melanomas. Our data identify the cytosine-deaminated CPD as the leading premutagenic lesion responsible for mutations in melanomas.

Drug–DNA complexation as the key factor in photosensitized thymine dimerization

2017 ◽  
Vol 19 (7) ◽  
pp. 4951-4955 ◽  
Author(s):  
M. Consuelo Cuquerella ◽  
Virginie Lhiaubet-Vallet ◽  
Miguel A. Miranda ◽  
Francisco Bosca
Keyword(s):  
Dna Damage ◽  
Crucial Role ◽  
Transient Absorption ◽  
Cyclobutane Pyrimidine Dimers ◽  
Absorption And Emission ◽  
Pyrimidine Dimers ◽  
Key Factor

The crucial role of photosensitizer@DNA complexation in the formation of cyclobutane pyrimidine dimers (CPDs) has been demonstrated using femtosecond and nanosecond transient absorption and emission measurements in combination with in vitro DNA damage assays.

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

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