What Is a Phosphodiester Bond?

A phosphodiester bond is the linkage between two deoxyribose or ribose sugars on adjacent nucleotides. Phosphodiester bonds make up the backbone of a strand of deoxyribose nucleic acid, or DNA.

A phosphodiester bond consists of a phosphorous atom and two ester bonds. Phosphodiester bonds are strong covalent bonds and resistant to attack. These bonds stabilize the structure of DNA and prevent it from being degraded and broken down. DNA contains the genetic code in the form of nucleotides for every cell. This code must be read in a specific order for the cell to function and develop properly. The structure of DNA holds the nucleotides in place using phosphodiester bonds. The phosphate groups in these bonds are negatively charged and cause the phosphates to move to opposite ends of the DNA strand. The phosphates are neutralized by proteins called histones. Phosphates can also be held in place by metal ions and polyamines. Phosphodiester bonds are created by linking phosphate and two free hydroxyl groups of a deoxyribose molecule. This continuous linking creates a chain, also known as the backbone of DNA. In order for phosphodiester bonds to form, pyrophosphates, compounds such as salts and esters, must break apart and catalyze the reaction.