Guanine on DNA (G)

Guanine is a purine nitrogenous base found in both DNA and RNA, with the chemical formula C₅H₅N₅O, and is symbolized by “G”. In DNA, guanine base pairs specifically with cytosine via three hydrogen bonds, contributing significant stability to the double helix. The sequence of guanine and other bases encodes the genetic information necessary for all cellular functions. Guanine’s position and chemical integrity are essential for accurate replication, transcription, and cell viability; chemical modifications to guanine underpin many forms of mutagenesis relevant to cancer and other diseases. Drugs that modify DNA can act at guanine nucleotides, not as “targeting guanine” per se, but by exploiting its reactivity (e.g., alkylation and oxidation sites). Guanine on DNA is not a classical drug target, though its modification forms the mechanistic basis for both therapeutic and toxic DNA-targeting agents in oncology and related fields.

Other names

Gguanosine (as nucleoside)DNA guanineguanine base

Alkylation (DNA damaging agents form covalent adducts with guanine N7); Methylation (e.g., methylating agents act at guanine positions, leading to mutagenic lesions); Intercalation (some drugs or toxins intercalate between guanine-cytosine pairs, affecting structure and replication)