DNAクランプ/複製DNAポリメラーゼ複合体におけるDNA合成・修正スイッチング機構 [in Japanese] Structural Determinant for Switching between the Polymerase and Exonuclease Modes in the PCNA-Replicative DNA Polymerase Complex [in Japanese]
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Proliferating cell nuclear antigen (PCNA) is responsible for the processivity of DNA polymerase. We determined the crystal structure of <i>Pyrococcus furiosus</i> DNA polymerase (PfuPol) complexed with a cognate monomeric PCNA, which allowed us to construct a convincing model of the polymerase-PCNA ring interaction. Electron microscopy analyses confirmed that this complex structure exists among the multiple functional configurations in solution. Together with data from mutational analyses, this structural study indicated that the novel interaction between a stretched loop of PCNA and the PfuPol Thumb domain is quite important, in addition to the authentic PCNA-polymerase recognition site (PIP box). A comparison of the present structures with the previously reported structures of polymerases complexed with DNA suggested that the second interaction site plays a crucial role in switching between the polymerase and exonuclease modes, by stabilizing only the polymerase mode. This proposed mechanism of fidelity control of replicative DNA polymerases was supported by experiments, in which a mutation within the second interaction site caused an enhancement in the exonuclease activity in the presence of PCNA.
- Nihon Kessho Gakkaishi
Nihon Kessho Gakkaishi 52(4), 201-207, 2010-08-31
The Crystallographic Society of Japan