DNA guanine nucleobase (G)

DNA guanine nucleobases are one of the four fundamental nitrogenous bases that encode genetic information within the cell nucleus, pairing with cytosine to stabilize the DNA double helix (National Center for Biotechnology Information, 2023). In the context of pharmacology, guanine is a critical molecular target for cytotoxic chemotherapy, particularly for alkylating agents and platinum-based compounds (PubMed PMID: 17305385). These drugs exploit the high nucleophilicity of the guanine N7 position to form covalent adducts and cross-links that disrupt essential cellular processes such as DNA replication and transcription (PubMed PMID: 11511583). The resulting genomic instability and physical blockage of polymerase enzymes trigger apoptotic pathways, making these agents effective against rapidly proliferating tumor cells (StatPearls, 2023). However, because these drugs do not discriminate between cancerous and healthy DNA, they often cause significant systemic toxicities, including bone marrow suppression and organ damage (PubMed PMID: 15501967). The clinical efficacy of targeting guanine is often modulated by DNA repair enzymes like MGMT, which can remove drug-induced modifications and contribute to chemoresistance (PubMed PMID: 15728810).

Other names

Guanine2-amino-1,9-dihydro-6H-purin-6-onedGDeoxyguanosineN7-guanine

Drugs target guanine through covalent modification, primarily at the N7 or O6 positions of the purine ring. Alkylating agents transfer alkyl groups to these sites, while platinum-based drugs form coordination complexes that result in intrastrand or interstrand DNA cross-links. These modifications distort the DNA structure, inhibiting the progression of DNA and RNA polymerases, which leads to cell cycle arrest and the induction of apoptosis (PubMed PMID: 17305385, 11511583).