Assembly of a chromosomal replication machine: two DNA polymerases, a clamp loader, and sliding clamps in one holoenzyme particle. IV. ATP-binding site mutants identify the clamp loader.

The gamma complex (gamma delta delta' chi psi) and tau complex (tau delta delta' chi psi) clamp loaders require ATP hydrolysis to load beta sliding clamps onto DNA. The beta sliding clamp tethers the polymerase (Pol) III* replicase to DNA for processive synthesis. Pol III* contains both gamma and tau, but only one each of the delta, delta', chi, and psi… (More)