Deoxyadenosine

File:Deoxyadenosine-3D-spacefill.png

3D space-filling model of deoxyadenosine

Deoxyadenosine is a deoxyribonucleoside that is composed of the purine base adenine attached to a deoxyribose sugar. It is one of the four nucleoside building blocks of DNA, the others being deoxycytidine, deoxyguanosine, and thymidine.

Structure

Deoxyadenosine consists of the adenine base linked to a deoxyribose sugar via a _-N9-glycosidic bond. The absence of a hydroxyl group at the 2' position of the ribose sugar distinguishes it from adenosine, which is a component of RNA.

Function

In the context of DNA, deoxyadenosine pairs with thymine through two hydrogen bonds, contributing to the stability of the double helix structure. It plays a crucial role in the storage and transmission of genetic information.

Synthesis

Deoxyadenosine is synthesized in cells through the reduction of adenosine diphosphate (ADP) to deoxyadenosine diphosphate (dADP) by the enzyme ribonucleotide reductase. This is followed by the conversion of dADP to deoxyadenosine triphosphate (dATP), which is then incorporated into DNA during DNA replication.

Metabolism

Deoxyadenosine is metabolized by the enzyme adenosine deaminase to deoxyinosine, which is further broken down into hypoxanthine and eventually into uric acid. Deficiency in adenosine deaminase can lead to the accumulation of deoxyadenosine, which is toxic to lymphocytes and can result in severe combined immunodeficiency (SCID).

Clinical Significance

The accumulation of deoxyadenosine due to adenosine deaminase deficiency is a key factor in the pathogenesis of SCID. This condition is characterized by a severely compromised immune system, making individuals highly susceptible to infections. Treatment options include enzyme replacement therapy and gene therapy.

Related pages

• DNA
• Nucleoside
• Adenine
• Deoxyribose
• Adenosine deaminase