Various octadeoxynucleotides containing uracil at different positions were synthesized and submitted to the action of Escherichia coli and Micrococcus luteus uracil-DNA glycosylases. A uracil residue situated at the 5'-end was excised by the M.luteus enzyme but not by the E.coli one. Uracil residues located at the ultimate and penultimate positions at the 3'-end were not cleaved by either enzym...

We report that deamination coupled with 5-carboxyvinyldeoxyuridine-mediated photobranching causes the heat-induced transition of cytosine to uracil with high efficiency without any side reaction.

The prokaryotic DNA(cytosine-5)methyltransferase M.SssI shares the specificity of eukaryotic DNA methyltransferases (CG) and is an important model and experimental tool in the study of eukaryotic DNA methylation. Previously, M.SssI was shown to be able to catalyze deamination of the target cytosine to uracil if the methyl donor S-adenosyl-methionine (SAM) was missing from the reaction. To test ...

This work presents the results of a theoretical study that analyzed possibility nucleobases to form in interstellar medium, Horsehead nebula, which is region considered an archetype molecular cloud. Performing Meudon PDR code, reactions nitrogen bases formation from formamide, precursor compound identified several environment, where simulated. The model showed at least cytosine and uracil prese...

Genomes of hyperthermophiles are facing a severe challenge due to increased deamination rates cytosine induced by high temperature, which could be counteracted base excision repair mediated uracil DNA glycosylase (UDG) or other pathways. Our previous work has shown that the two UDGs (Tba UDG247 and Tba UDG194) encoded genome hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 can remove ...

Laboratory experiments have shown that the UV photo-irradiation of low-temperature ices of astrophysical interest leads to the formation of organic molecules, including molecules important for biology such as amino acids, quinones, and amphiphiles. When pyrimidine is introduced into these ices, the products of irradiation include the nucleobases uracil, cytosine, and thymine, the informational ...

OsO4 selectively forms thymine glycol lesions in DNA. In the past, OsO4-treated DNA has been used as a substrate in studies of DNA repair utilizing base-excision repair enzymes such as DNA glycosylases. There is, however, no information available on the chemical identity of other OsO4-induced base lesions in DNA. A complete knowledge of such DNA lesions may be of importance for repair studies. ...

The informational subunits of RNA or DNA consist of substituted N-heterocyclic compounds that fall into two groups: those based on purine (C₅H₄N₄) (adenine and guanine) and those based on pyrimidine (C₄H₄N₂) (uracil, cytosine, and thymine). Although not yet detected in the interstellar medium, N-heterocycles, including the nucleobase uracil, have been reported in carbonaceous chondrites. Recent...

Recent studies using anion exclusion chromatography have suggested that uracil is misincorporated into the DNA of patients with megaloblastic anemia to levels detectable by nonradioactive methods. We have investigated the nucleotide composition of DNA from the bone marrow mononuclear cells of eight patients with cobalamin deficiency and compared this with that found in normal subjects. The medi...

APOBEC3B (A3B) is a cytosine deaminase that converts to uracil in single-stranded DNA. Cytosine-to-thymine and cytosine-to-guanine base substitution mutations trinucleotide motifs (APOBEC mutational signatures) were found various cancers including lymphoid hematological malignancies such as multiple myeloma A3B has been shown be an enzymatic source of those cancers. Although the importance bein...