DNA N7 position of guanine (N7-G)

The DNA N7 position of guanine is the most nucleophilic and accessible site within the major groove of the DNA double helix, making it a primary target for many electrophilic anticancer drugs [1.3.1, 1.4.1]. Therapeutic agents such as platinum-based compounds (e.g., cisplatin) and alkylating agents (e.g., nitrogen mustards) form stable covalent bonds at this position, resulting in the formation of DNA adducts and cross-links [1.4.1, 1.5.1]. These lesions physically obstruct the progression of DNA and RNA polymerases, thereby inhibiting essential cellular processes such as DNA replication and transcription [1.3.1, 1.4.5]. In rapidly dividing cancer cells, the accumulation of these DNA modifications triggers DNA damage response pathways, leading to cell cycle arrest and programmed cell death (apoptosis) [1.4.1, 1.5.2]. While targeting the N7 position is a cornerstone of many effective chemotherapy regimens, it also poses significant safety challenges, including myelosuppression and the risk of secondary malignancies due to the genotoxic nature of the resulting DNA damage [1.4.3, 1.5.1].

Other names

N7-guanineN7-dGGuanine N7N7-position of guanineN7-alkylguanine

Alkylating and platinum-based agents act as electrophiles that covalently bind to the nucleophilic N7 position of guanine. This binding forms DNA adducts and cross-links (intrastrand and interstrand), which distort the DNA helix and block the progression of replication and transcription machinery, leading to DNA damage responses and apoptosis.