Processivity

From WikiMD's Wellness Encyclopedia

Processivity is a term used in molecular biology to describe the ability of an enzyme to continuously perform its catalytic function without dissociating from its substrate. This property is particularly important in DNA replication, where the DNA polymerase enzyme must remain attached to the DNA strand to add nucleotides and form the new DNA strand.

Overview[edit | edit source]

Processivity is a key factor in the efficiency of DNA replication. The higher the processivity of a DNA polymerase, the more nucleotides it can add to the new DNA strand before it dissociates. This allows the replication process to proceed more quickly and accurately.

DNA polymerases achieve high processivity through the use of a sliding clamp, a protein that encircles the DNA strand and tethers the polymerase to the DNA. The sliding clamp is loaded onto the DNA by a clamp loader complex, which uses energy from ATP hydrolysis to open the clamp and place it around the DNA.

Role in DNA Replication[edit | edit source]

During DNA replication, the DNA polymerase enzyme synthesizes a new DNA strand by adding nucleotides to the 3' end of the existing strand. The processivity of the polymerase determines how many nucleotides it can add before it dissociates from the DNA.

The sliding clamp increases the processivity of the DNA polymerase by preventing it from dissociating from the DNA. This allows the polymerase to add many more nucleotides to the new strand before it has to reattach to the DNA, increasing the speed and efficiency of DNA replication.

Clinical Significance[edit | edit source]

Processivity is also important in the replication of viruses. Viral DNA polymerases often have high processivity, which allows them to rapidly replicate the viral genome and produce many copies of the virus. This high processivity is a target for antiviral drugs, which aim to inhibit the replication of the virus by reducing the processivity of the viral DNA polymerase.

Processivity Resources

Contributors: Prab R. Tumpati, MD