Deoxyguanosine

3D model of deoxyadenosine, a related nucleoside

Deoxyguanosine is a nucleoside comprising the purine base guanine attached to a deoxyribose sugar. It is one of the four nucleosides that make up DNA, the others being deoxyadenosine, deoxycytidine, and deoxythymidine.

Structure

Deoxyguanosine consists of a guanine 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 guanosine, which is found in RNA.

Function

In the context of DNA, deoxyguanosine pairs with deoxycytidine through three hydrogen bonds, contributing to the stability of the DNA double helix. This base pairing is crucial for the accurate replication and transcription of genetic information.

Biological Importance

Deoxyguanosine is involved in various cellular processes, including DNA replication and repair. It is a substrate for DNA polymerase during DNA synthesis. Additionally, deoxyguanosine can be phosphorylated to form deoxyguanosine triphosphate (dGTP), which is an essential building block for DNA synthesis.

Metabolism

Deoxyguanosine is metabolized by the enzyme purine nucleoside phosphorylase to guanine and deoxyribose-1-phosphate. This process is part of the purine salvage pathway, which recycles purines to synthesize new nucleotides.

Clinical Significance

Abnormalities in deoxyguanosine metabolism can lead to various disorders. For example, deficiencies in enzymes involved in its metabolism can result in immunodeficiency diseases due to impaired DNA synthesis in rapidly dividing cells, such as lymphocytes.

Related Pages

• DNA
• Nucleoside
• Guanine
• Deoxyribose
• Purine