Sliding clamp

Definition

A sliding clamp is a protein complex that encircles DNA and anchors DNA polymerase during replication, ensuring high processivity. It allows the polymerase to synthesize long stretches of DNA without dissociating.

5 Must Know Facts For Your Next Test

1. The sliding clamp in E. coli is known as the beta-clamp and is composed of two identical subunits.
2. In eukaryotes, the sliding clamp is called PCNA (Proliferating Cell Nuclear Antigen).
3. The sliding clamp interacts with the DNA polymerase through specific binding sites.
4. Sliding clamps are loaded onto DNA by a clamp loader complex, which requires ATP hydrolysis.
5. Mutations in sliding clamp proteins can lead to defects in DNA replication and are linked to various diseases.

Review Questions

Related terms

DNA Polymerase:

An enzyme that synthesizes new strands of DNA complementary to the template strand.

Clamp Loader Complex: A protein complex that loads the sliding clamp onto DNA, requiring ATP.

Processivity: The ability of an enzyme to catalyze consecutive reactions without releasing its substrate.