DNA guanine residue (G (for guanine, the base; no standard abbreviation for "DNA guanine residue" as a target))

DNA **guanine residues**, also known simply as *guanines*, are one of four main nitrogenous bases found within deoxyribonucleic acid (**DNA**) molecules—the others being adenine, cytosine, and thymine. Each residue consists chemically of a purine ring system containing carbon, nitrogen, hydrogen, and oxygen atoms (C₅H₅N₅O)[1]. In double-stranded DNA's helical structure they pair specifically with cytosines via three hydrogen bonds—a key feature ensuring accurate storage and transmission of genetic information during cell division[6]. The sequence order—including that of all incorporated *guanines*—determines gene function across all living organisms[3][5]. While *guanine residues* themselves are not typical drug targets like proteins or enzymes—and thus do not have canonical abbreviations beyond “G”—they play critical roles both structurally within chromosomes/genomes [4]and functionally by encoding hereditary instructions [7]. Chemical modifications at these sites underlie mechanisms for several classes of anticancer therapies but also pose risks due to their essential role throughout normal cellular genomes.

Other names

Guanine in DNAG base in DNADeoxyguanosine residue (when referring to nucleotide form)Purine base G

1. Alkylation/crosslinking: Covalent modification at N7/O6 positions on deoxyguanosine disrupts base pairing/replication. 2. Inhibition of synthesis/incorporation: Antimetabolites may prevent proper addition of dGTP into growing strands.