Guanine residues in nuclear DNA (DNA-G)

Guanine residues in nuclear DNA serve as the fundamental molecular targets for several major classes of cytotoxic chemotherapy, including alkylating agents and platinum-based coordination complexes (NIH). These therapeutic agents exploit the nucleophilic nature of guanine, specifically at the N7 and O6 atoms, to form stable covalent bonds or adducts (PubChem). The resulting structural alterations, such as interstrand cross-links, prevent the DNA double helix from unwinding, thereby stalling DNA polymerase and RNA polymerase activities (StatPearls). This disruption of DNA replication and transcription is particularly lethal to rapidly proliferating neoplastic cells, which often have diminished capacity for DNA repair compared to normal cells (PubMed). However, because these interactions are not site-specific within the genome, they can lead to significant systemic toxicities, including bone marrow suppression and the potential for secondary cancers due to permanent mutations in healthy tissues (NIH).

Other names

Nuclear DNA guanineN7-guanineO6-guanineDeoxyguanine residuesDNA guanine bases

Chemotherapeutic agents target guanine residues by forming covalent adducts, primarily at the N7 or O6 positions (PubChem). Alkylating agents transfer alkyl groups to guanine, while platinum compounds form coordination bonds, leading to intrastrand or interstrand cross-linking (StatPearls). These lesions distort the DNA structure, inhibiting DNA polymerase and RNA polymerase, which triggers the DNA damage response and leads to programmed cell death (PubMed).