The Human Lagging Strand DNA Polymerase δ Holoenzyme Is Distributive
The Human Lagging Strand DNA Polymerase δ Holoenzyme Is Distributive
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DOI：
10.1074/jbc.m112.404319
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发表时间：
2012-11-09
影响因子：
4.8
通讯作者：
Benkovic, Stephen J.
中科院分区：
文献类型：
--
作者：
Hu, Zhenxin;Perumal, Senthil K.;Benkovic, Stephen J.
Polymerase delta is widely accepted as the lagging strand replicative DNA polymerase in eukaryotic cells. It forms a replication complex in the presence of replication factor C and proliferating cell nuclear antigen to perform efficient DNA synthesis in vivo. In this study, the human lagging strand holoenzyme was reconstituted in vitro. The rate of DNA synthesis of this holoenzyme, measured with a singly primed ssM13 DNA substrate, is 4.0 +/- 0.4 nucleotides. Results from adenosine 5'-(3-thiotriphosphate) tetralithium salt (ATP gamma S) inhibition experiments revealed the nonprocessive characteristic of the human DNA polymerase (Pol delta) holoenzyme (150 bp for one binding event), consistent with data from chase experiments with catalytically inactive mutant Pol delta(AA.) The ATPase activity of replication factor C was characterized and found to be stimulated similar to 10-fold in the presence of both proliferating cell nuclear antigen and DNA, but the activity was not shut down by Pol delta in accord with rapid association/dissociation of the holoenzyme to/from DNA. It is noted that high concentrations of ATP inhibit the holoenzyme DNA synthesis activity, most likely due to its inhibition of the clamp loading process.
