DNA-7-methylguanine glycosylase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: DNA containing 7-methylguanine + H2O = DNA with abasic site + 7-methylguanine. This reaction is the hydrolysis of DNA by cleavage of the N-C1' glycosidic bond between the damaged DNA 7-methylguanine and the deoxyribose sugar to remove the 7-methylguanine, leaving an abasic site. [GOC:jl, PMID:16468998]
DNA-7-methylguanine glycosylase activity is a crucial DNA repair mechanism that removes 7-methylguanine (7meG), a promutagenic lesion formed by alkylating agents such as methylating carcinogens, from DNA. This activity is catalyzed by a family of enzymes known as methylguanine methyltransferases (MGMTs). MGMTs function by directly transferring the methyl group from 7meG to a cysteine residue within the active site of the enzyme, effectively removing the lesion from the DNA. This transfer reaction is irreversible and results in the inactivation of the MGMT protein, making it a stoichiometric repair enzyme. The removal of 7meG by MGMT is essential for maintaining genomic integrity and preventing mutations that can lead to cancer. MGMT activity is particularly important in protecting cells from the deleterious effects of alkylating agents, which are used in cancer chemotherapy. In addition to 7meG, MGMTs can also remove other alkylated purines, including O6-methylguanine, from DNA. This DNA repair mechanism is highly specific, ensuring that only the damaged base is removed without affecting the integrity of the surrounding DNA sequence. The MGMT-mediated repair process plays a critical role in preventing mutations, preserving genome stability, and protecting cells from the detrimental effects of alkylating agents.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| DNA-3-methyladenine glycosylase | A DNA-3-methyladenine glycosylase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P29372] | Homo sapiens (human) |
Compounds (4)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| aurintricarboxylic acid | aurintricarboxylic acid : A member of the class of quinomethanes that is 3-methylidene-6-oxocyclohexa-1,4-diene-1-carboxylic acid in which the methylidene hydrogens are replaced by 4-carboxy-3-hydroxyphenyl groups. The trisodium salt is the biological stain 'chrome violet CG' while the triammonium salt is 'aluminon'. Aurintricarboxylic Acid: A dye which inhibits protein biosynthesis at the initial stages. The ammonium salt (aluminon) is a reagent for the colorimetric estimation of aluminum in water, foods, and tissues. | monohydroxybenzoic acid; quinomethanes; tricarboxylic acid | fluorochrome; histological dye; insulin-like growth factor receptor 1 antagonist |
| gossypol | Gossypol: A dimeric sesquiterpene found in cottonseed (GOSSYPIUM). The (-) isomer is active as a male contraceptive (CONTRACEPTIVE AGENTS, MALE) whereas toxic symptoms are associated with the (+) isomer. | ||
| mitoxantrone hydrochloride | hydrochloride | antineoplastic agent | |
| morin | morin : A pentahydroxyflavone that is 7-hydroxyflavonol bearing three additional hydroxy substituents at positions 2' 4' and 5. morin: a light yellowish pigment found in the wood of old fustic (Chlorophora tinctoria) | 7-hydroxyflavonol; pentahydroxyflavone | angiogenesis modulating agent; anti-inflammatory agent; antibacterial agent; antihypertensive agent; antineoplastic agent; antioxidant; EC 5.99.1.2 (DNA topoisomerase) inhibitor; hepatoprotective agent; metabolite; neuroprotective agent |