The heterodimeric primase from the euryarchaeon Pyrococcus abyssi:: A multifunctional enzyme for initiation and repair?
The heterodimeric primase from the euryarchaeon Pyrococcus abyssi:: A multifunctional enzyme for initiation and repair?
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DOI：
10.1016/j.jmb.2007.10.015
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发表时间：
2007-12-14
影响因子：
5.6
通讯作者：
Raffin, Jean-Paul
中科院分区：
文献类型：
--
作者：
Le Breton, Magali;Henneke, Ghislaine;Raffin, Jean-Paul
我们报告的DNA引物酶复合物的超嗜热古菌Pyrococcus abyssi（Pab）的表征。Pab DNA引发酶复合物由蛋白质Pabp 41和Pabp 46组成，它们分别与真核聚合酶α-引发酶复合物的p49和p58亚基显示序列相似性。这两个亚基的表达，纯化和表征。Pabp 41亚基单独没有RNA合成活性，但可以合成长（高达3 kb）的DNA链。Pabp 46亚基的加入增加了DNA合成的速率，但降低了合成的DNA片段的长度，并赋予了RNA合成能力。此外，在我们的实验条件下，Pab DNA引发酶对核糖核苷酸和脱氧核糖核苷酸具有相当的亲和力，并且其活性依赖于Mg ~（2+）和Mn ~（2+）的存在。有趣的是，Pab DNA引发酶也显示DNA聚合酶，缺口填充和链置换活动。在Haloferax volcanii中进行的遗传分析表明，真核生物型异二聚体引发酶对于古细菌细胞中的生存是必不可少的。我们的研究结果是有利于一个多功能的古细菌引发酶参与启动和修复。(c)2007爱思唯尔有限公司保留所有权利。
We report on the characterization of the DNA primase complex of the hyperthermophilic archaeon Pyrococcus abyssi (Pab). The Pab DNA primase complex is composed of the proteins Pabp41 and Pabp46, which show sequence similarities to the p49 and p58 subunits, respectively, of the eukaryotic polymerase alpha-primase complex. Both subunits were expressed, purified, and characterized. The Pabp41 subunit alone had no RNA synthesis activity but could synthesize long (up to 3 kb) DNA strands. Addition of the Pabp46 subunit increased the rate of DNA synthesis but decreased the length of the DNA fragments synthesized and conferred RNA synthesis capability. Moreover, in our experimental conditions, Pab DNA primase had comparable affinities for ribonucleotides and deoxyribonu-cleotides, and its activity was dependent on the presence of Mg2+ and Mn2+. Interestingly, Pab DNA primase also displayed DNA polymerase, gap-filling, and strand-displacement activities. Genetic analyses undertaken in Haloferax volcanii suggested that the eukaryotic-type heterodimeric primase is essential for survival in archaeal cells. Our results are in favor of a multifunctional archaeal primase involved in priming and repair. (c) 2007 Elsevier Ltd. All rights reserved.