# Phosphodiester Bond --- A **phosphodiester bond**, or sometimes called **phosphodiester linkage** is a [[chemical bond]] formed when a phosphate group binds to a sugar group. Phosphodiester bonds form the [[DNA structure|sugar-phosphate backbone]] of DNA and RNA. **Phosphodiesterase** is an enzyme that breaks phosphodiester bonds. Notably they work to deactivate [[second messengers]] like cAMP by breaking their phosphodiester bond. ![[phosphodiester bond.png]] %%page ender below%% ___