Phosphodiester bonds make up the
backbones of
DNA and
RNA. In the phosphodiester bonds of nucleic acids, a phosphate is attached to the 5' carbon of one nucleoside and to the 3' carbon of the adjacent nucleoside. Specifically, it is the phosphodiester bonds that link the
3' carbon atom of one sugar molecule and the 5' carbon atom of another (hence the name 3', 5' phosphodiester linkage used with reference to this kind of bond in DNA and RNA chains). The involved saccharide groups are
deoxyribose in DNA and
ribose in RNA. In order for the phosphodiester bond to form
, joining the
nucleosides, the tri-phosphate or di-phosphate forms of the nucleotide building blocks are broken apart to give off energy required to drive the
enzyme-catalyzed reaction. In DNA replication, for example, formation of the phosphodiester bonds is catalyzed by a
DNA polymerase enzyme, using a pair of
magnesium cations and other supporting structures. Phosphodiesters are negatively charged at
pH 7. The negative charge attracts
histones, metal cations such as
magnesium, and
polyamines [needs citation]. Repulsion between these negative charges influences the conformation of the polynucleic acids. == Breaking the Phosphodiester Bond ==