DNA polymerase beta

DNA Polymerase Beta

DNA Polymerase Beta structure

DNA polymerase beta (abbreviated as Pol β) is a key enzyme involved in DNA replication and repair processes. It plays a crucial role in maintaining the integrity of the genome by accurately copying and repairing DNA molecules. DNA polymerase beta is a member of the X family of DNA polymerases and is found in most eukaryotic organisms, including humans.

Structure

DNA polymerase beta is a small enzyme consisting of a single polypeptide chain with a molecular weight of approximately 39 kilodaltons. It is composed of a palm domain, a thumb domain, and a fingers domain. The palm domain contains the active site, where DNA synthesis takes place, while the thumb and fingers domains are involved in DNA binding and stabilization.

Function

The primary function of DNA polymerase beta is to synthesize short DNA fragments during DNA repair processes, particularly in the base excision repair pathway. It is responsible for filling in the gaps left after damaged or incorrect nucleotides have been removed from the DNA strand. DNA polymerase beta also plays a role in DNA replication, where it helps to replicate the lagging strand by synthesizing short Okazaki fragments.

Role in DNA Repair

DNA polymerase beta is essential for maintaining genomic stability by participating in the repair of damaged DNA. It is particularly involved in the repair of DNA lesions caused by oxidative stress and exposure to certain chemicals. The enzyme is capable of accurately inserting nucleotides opposite damaged bases, ensuring the faithful restoration of the DNA sequence.

Importance in Human Health

Mutations in the gene encoding DNA polymerase beta have been associated with various diseases, including cancer and neurological disorders. Defects in DNA repair mechanisms can lead to the accumulation of DNA damage, increasing the risk of genomic instability and the development of cancer. Additionally, deficiencies in DNA polymerase beta have been linked to neurodegenerative diseases such as Parkinson's and Alzheimer's.

See Also

• DNA replication
• DNA repair
• Base excision repair
• Okazaki fragments