Clamp loader structure predicts the architecture of DNA polymerase III holoenzyme and RFC

Recent determinations of the crystal structure of the Escherichia coli gamm a complex and delta-beta assembly have shed light on the bacterial clamp lo ading reaction. In this review, we discuss the structures of delta-beta and the gamma (3)delta delta ' complex and its mechanism of action as a clamp loader of the E. coli beta sliding clamp. We also expand upon the implicati ons of the structural findings to the structure and function of the eukaryo tic clamp loader, RFC, and the structure of E. coli DNA polymerase III holo enzyme.