deoxynucleotiden

Deoxynucleotides are the building blocks of DNA. Each unit consists of three components: a 2'-deoxyribose sugar, a nitrogenous base (adenine, thymine, cytosine, or guanine), and one to three phosphate groups. When the molecule contains three phosphates, it's called a deoxynucleotide triphosphate (dNTP); two phosphates correspond to a diphosphate (dNDP), and one phosphate to a monophosphate (dNMP). The four base types correspond to dATP, dTTP, dCTP, and dGTP.

In DNA replication and repair, DNA polymerases use dNTPs as substrates, adding the corresponding deoxyribonucleotide to the 3' end of a growing DNA strand and releasing pyrophosphate. The sugar–phosphate backbone of DNA is formed by phosphodiester linkages between the 5' phosphate of one nucleotide and the 3' hydroxyl of the next. The 2'-deoxyrose sugar lacking a 2'-hydroxyl makes DNA more chemically stable than RNA.

Within cells, dNTP pools are carefully balanced through de novo synthesis and salvage pathways; imbalances can increase mutation risk or stall replication. Deoxynucleotides also serve as precursors in nucleotide metabolism, and their triphosphate forms are essential for DNA synthesis.