Interaction between the replicational initiator DnaA and the DNA polymerase components

复制起始子 DnaA 和 DNA 聚合酶组分之间的相互作用

基本信息

批准号：
10680616
负责人：
KATAYAMA Tsutomu
金额：
$ 2.18万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680616/
关键词：
chromosome DNA replication ATP DnaA DNA polymerase Sliding clamp Replicational initiation Cell cycle スライディング・クランプ染色体複製 otiC 大腸菌

项目摘要

In E. coli, DnaA protein forms a complex with the chromosomal replication origin (oriC). In this complex, DnaA opens the duplex DNA. This initiation activity of DnaA protein depends on ATP binding. On the generated single stranded region, DNA polymerase III, the replicase of chromosome, is loaded.We recently revealed that the hydrolysis of ATP bound to DnaA is accelerated by interaction with the sliding clamp of DNA polymerase III and a partially purified IdaB protein fraction. The sliding clamp is a ring-like configuration that is comprised from a dimer of the β subunit of the replicase and tethers DNA strand to the replicase. By this reaction, the ADP form of DnaA, an inactive form for initiation, is rapidly generated. We named this system RIDA for Regulatory Inactivation of DnaA, and suggested that RIDA is a main system to prevent extra initiations for maintaining the frequency of initiation only once per chromosome per cell cycle. Indeed, certain DnaA mutant proteins that are insensitive to a RIDA causes overinitiation of chromosomal replication. Moreover, we had in vivo evidence that RIDA depends on genes necessary for DNA replication. Content of the ATP form of DnaA in randomly dividing cells is 15 - 30% of total ATP/ADP-bound DnaA molecules, and when genes required for DNA replication were inactivated, the ATP-DnaA level increased up to 80%. These results suggest that the ATP-DnaA level is restrained during the cell cycle depending on DNA replication, which may be a key event to control the initiation cycle of chromosomal replication.

在大肠杆菌中，DNAA蛋白与染色体复制起源（ORIC）形成复合物。在这个复合物中，DNAA打开双链DNA。 DNAA蛋白的这种启动活性取决于ATP结合。在产生的单链区域，DNA聚合酶III（染色体的重复）被加载。我们最近透露，通过与DNA聚合酶III的滑动夹和部分纯化的IDAB蛋白质分数相互作用，与DNAA结合的ATP的水解加速了。滑动夹是一种环状构型，它由复制的β亚基的二聚体组成，而撕裂的DNA链DNA链到复制中。通过这种反应，DNAA的ADP形式是一种无效的主动性形式，迅速产生。我们命名了此系统RIDA用于调节DNAA的调节灭活，并建议RIDA是一个主要系统，以防止每个细胞周期每染色体每染色体每染色体一次保持主动频率的额外主动性。实际上，对RIDA不敏感的某些DNAA突变蛋白会导致染色体复制过度介绍。此外，我们有体内证据表明RIDA取决于DNA复制所需的基因。随机分裂细胞中DNAA的ATP形式的含量为总ATP/ADP结合的DNAA分子的15-30％，当灭活DNA复制所需的基因时，ATP-DNAA水平增加了80％。这些结果表明，根据DNA复制，在细胞周期中限制了ATP-DNAA水平，这可能是控制染色体复制的主动性周期的关键事件。