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DNA oxidation is the process of oxidative damage of deoxyribonucleic acid.As described in detail by Burrows et al., [1] 8-oxo-2'-deoxyguanosine (8-oxo-dG) is the most common oxidative lesion observed in duplex DNA because guanine has a lower one-electron reduction potential than the other nucleosides in DNA.
As shown by Zhou et al., [23] and illustrated below, oxidation of the guanine in the methylated CpG site, to form 5mCp-8-oxo-dG is the first step in demethylation. 8-oxo-dG complexed with OGG1 likely has a major role in facilitating thousands of rapid demethylations of methylated cytosines in CpG sites during formation of memory and further ...
Guanine, along with adenine and cytosine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA, and uracil only in RNA. Guanine has two tautomeric forms, the major keto form (see figures) and rare enol form. [citation needed] It binds to cytosine through three hydrogen bonds. In cytosine, the amino group acts as the ...
8-Oxoguanine (8-hydroxyguanine, 8-oxo-Gua, or OH 8 Gua) is one of the most common DNA lesions resulting from reactive oxygen species [2] modifying guanine, and can result in a mismatched pairing with adenine resulting in G to T and C to A substitutions in the genome. [3] In humans, it is primarily repaired by DNA glycosylase OGG1.
Of the natural nitrogenous bases of DNA, guanine is most prone to oxidation. Oxidation of guanine, also known as oxidative guanine damage, results in the formation of many products. These products trigger mutations, leading to DNA damage, and can pair with adenine and guanine through hydrogen bonding causing G-T transversions and G-C ...
Another possibility that has been proposed to account for much of the cytotoxicity of β-lactams focuses on the oxidation of the guanine nucleotide in the bacterial nucleotide pool. [15] The incorporation of oxidized guanine nucleotide into DNA could cause cytotoxicity.
Purines are biologically synthesized as nucleotides and in particular as ribotides, i.e. bases attached to ribose 5-phosphate.Both adenine and guanine are derived from the nucleotide inosine monophosphate (IMP), which is the first compound in the pathway to have a completely formed purine ring system.
DNA oxidation by reactive oxygen species preferentially occurs at a guanine in a methylated CpG site, because of a lowered ionization potential of guanine bases adjacent to 5-methylcytosine. [32] TET1 binds (is recruited to) the OGG1 bound to 8-OHdG (see figure). [25] This likely allows TET1 to demethylate an adjacent methylated cytosine.