Regulation of yeast DNA polymerase δ-mediated strand displacement synthesis by 5'-flaps.
Regulation of yeast DNA polymerase δ-mediated strand displacement synthesis by 5'-flaps.
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DOI：
10.1093/nar/gkv260
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发表时间：
2015-04-30
影响因子：
14.9
通讯作者：
Galletto R
中科院分区：
文献类型：
--
作者：
Koc KN;Stodola JL;Burgers PM;Galletto R
DNA 聚合酶 δ 的链置换活性受到其与增殖细胞核抗原 (PCNA) 相互作用的强烈刺激。然而，即使在不存在 PCNA 的情况下，3'–5' 核酸外切酶活性的失活也足以使聚合酶进行链置换。我们在体外检查了 Pol δ-exo− 进行链置换合成的基本生化特性，发现它受到待置换 DNA 链中 5'-襟翼的调节。在 Pol δ 进行链置换合成的条件下，长 5'-襟翼的存在或 ssDNA 反式添加会抑制这种活性。这表明酶上存在次级 DNA 结合位点，负责调节链置换活性。长 5'-襟翼的抑制作用可以通过其与单链 DNA 结合蛋白的相互作用来抑制。然而，皮瓣抑制的缓解并不仅仅源于复制蛋白 A 与皮瓣的结合并将其隔离。 Pol δ 与 PCNA 的相互作用通过掩盖聚合酶上的二级 DNA 位点消除了瓣介导的链置换合成抑制。这些数据表明，PCNA 除了增强聚合酶的持续合成能力之外，还是其他 Pol δ 活性的变构调节剂。
The strand displacement activity of DNA polymerase δ is strongly stimulated by its interaction with proliferating cell nuclear antigen (PCNA). However, inactivation of the 3′–5′ exonuclease activity is sufficient to allow the polymerase to carry out strand displacement even in the absence of PCNA. We have examined in vitro the basic biochemical properties that allow Pol δ-exo− to carry out strand displacement synthesis and discovered that it is regulated by the 5′-flaps in the DNA strand to be displaced. Under conditions where Pol δ carries out strand displacement synthesis, the presence of long 5′-flaps or addition in trans of ssDNA suppress this activity. This suggests the presence of a secondary DNA binding site on the enzyme that is responsible for modulation of strand displacement activity. The inhibitory effect of a long 5′-flap can be suppressed by its interaction with single-stranded DNA binding proteins. However, this relief of flap-inhibition does not simply originate from binding of Replication Protein A to the flap and sequestering it. Interaction of Pol δ with PCNA eliminates flap-mediated inhibition of strand displacement synthesis by masking the secondary DNA site on the polymerase. These data suggest that in addition to enhancing the processivity of the polymerase PCNA is an allosteric modulator of other Pol δ activities.
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影响因子：
11.4
作者：
MacNeill, SA;Moreno, S;Fantes, PA
通讯作者：
Fantes, PA
DOI：
10.1073/pnas.90.22.10881
发表时间：
1993-11-15
影响因子：
11.1
作者：
KABOORD, BF;BENKOVIC, SJ
通讯作者：
BENKOVIC, SJ
影响因子：
14.9
作者：
Fortune JM;Stith CM;Kissling GE;Burgers PM;Kunkel TA
通讯作者：
Kunkel TA
影响因子：
64.8
作者：
Bae, SH;Bae, KH;Seo, YS
通讯作者：
Seo, YS
DOI：
10.1073/pnas.251193198
发表时间：
2001-12-04
影响因子：
11.1
作者：
Maga, G;Villani, G;Hübscher, U
通讯作者：
Hübscher, U