Beta sliding clamp (β-clamp)

The **Beta sliding clamp** (β-clamp) is a homodimeric, ring-shaped protein complex essential for processive DNA replication and DNA repair in bacteria, especially *Escherichia coli* and related species[4][5][8]. It acts as a central hub by encircling double-stranded DNA and tethering DNA polymerase III and other proteins required for efficient DNA synthesis and repair, thereby preventing dissociation from the DNA template[2][3][4]. The β-clamp interacts with numerous binding partners through a conserved clamp binding motif and coordinates multiple activities at the replication fork. Its evolutionary homolog in eukaryotes is proliferating cell nuclear antigen (PCNA), but the bacterial β-clamp is structurally a homodimer, whereas PCNA is a homotrimer. Due to its essential role and structural divergence from eukaryotic processivity factors, the β-clamp is under investigation as a novel antibacterial drug target, with some nonsteroidal anti-inflammatory drugs and small-molecule inhibitors demonstrating weak to moderate activity against *E. coli* β-clamp in vitro[5][6].

Other names

DNA sliding clampBeta clampDNA clampdnaN (in E. coli)Sliding clamp protein

Allosteric inhibition of protein-protein interactions (block protein binding pocket in β-clamp)[5][6]; Competitively block clamp-binding motif access (for DNA polymerases and repair factors)[6]