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Home > Phosphodiester bonds


 

A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a phosphate group and two other molecules over two ester bonds. Phosphodiester bonds are central to all life on Earth as they make up the backbone of the strands of DNA. In DNA and RNA, the phosphodiester bond is the linkage between the 3' Carbon atom and the 5' Carbon of the ribose sugar.

The phosphate groups in the phosphodiester bond are very negatively charged. Because the phosphate groups are so negatively charged, there is a large repulsion which forces the phosphates to take opposite sides of the DNA strands.

In order for the phosphodiester bond to be formed and the nucleotides to be joined, 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. When a single phosphate or two phosphates known as pyrophosphates break away and catalyze the reaction, the phosphodiester bond is formed.

Phosphodiester bonds can be catalyzed by the action of phosphodiesterases which play an important role in repairing DNA sequences.

In biological systems, the phosphodiester bond between two ribonucleotides can be broken by alkaline hydrolysisAlkaline hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water in a solution with a pH greater than 7. In cellular systems, the phosphodiester bond between two ribonucleotides can be broken b because of the free 2' hydroxyl group.

1 Enzyme activity

A phosphodiesterase is an enzyme that catalyzes the hydrolysisHydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water. This is distinct from a hydration reaction, in which water molecules are added to a substance, but no cleavage occurs. Types Hydrolysis of phosphodiester bonds, for instance a bond in a molecule of cyclic AMPCyclic adenosine monophosphate cAMP cyclic AMP or 3'-5'-cyclic adenosine monophosphate) is a molecule that is important in many biological processes; it is derived from adenosine triphosphate (ATP). cAMP is a second messenger, used for intracellular signa or cyclic GMPsecond messenger derived from GTP. Cyclic guanosine monophosphate cGMP is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP, most notably by activating intracellular protein kinases in resp.

An enzyme that plays an important role in the repair of oxidative DNA damageDNA repair is a process constantly operating in each cell of a living being; it is essential to survival because it protects the genome from damage. In human cells, both normal metabolic activities and environmental factors (such as UV rays) can cause DNA is the 3'-phosphodiesterase.

During the replication of DNA, there is a hole between the phosphates in the backbone left by DNA polymerase I. DNA ligase is able to form a phosphodiester bond between the nucleotides.



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