β-sliding clamp mainly increases
Beta sliding clamp is homodimer forming doughnut-shaped ring encircling DNA, each monomer contains three domains structurally analogous to eukaryotic PCNA trimer. It binds directly to alpha polymerase subunit and to DNA phosphate backbone tethering polymerase to template without ATP hydrolysis. By preventing diffusion away, it raises processivity from about 10 nucleotides to more than 50,000 nucleotides per binding event. Clamp does not alter catalytic rate or nucleotide discrimination but ensures polymerase remains attached during rapid movement essential for coordinated leading lagging synth
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 5: Beta clamp structure and role in Pol III processivity
