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Assembly of Replicative Complexes

复制复合体的组装

基本信息

批准号：
7988482
负责人：
CHARLES S MCHENRY
金额：
$ 13.79万
依托单位：
UNIVERSITY OF COLORADO
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-01-21 至 2010-12-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant) The DNA polymerase III holoenzyme of E. coli is a prototypical replicative complex, exhibiting properties in common with other cellular replicases, including a high rate of processive elongation and the ability to interact with other proteins at the replication fork, establishing the communication channels necessary to coordinate the events required for efficient chromosomal replication. A key component of all cellular replicases is a multisubunit assembly of homologous proteins that require ATP to assemble a "sliding clamp processivity factor" onto primer termini. In E. coli, this function is served by the DnaX complex, DnaX3deltadelta'/khi/psi. The dna X gene of E. coli encodes two distinct products: i, the full-length translation product and gamma, a shorter protein that arises by translational frameshifting. During the next grant period, we will study i) the assembly pathway of DNA polymerase III holoenzyme, with emphasis on the role of Pol III in steering the assembly pathway to permit a unique arrangement of DnaX subunits, ii) determine the changes in macromolecular interactions that occur during loading of the beta2 sliding clamp onto primed DNA by the DnaX complex 'clamp loader,' iii) determine the mechanism of ATPgammaS-assisted initiation complex formation that proceeds without nucleotide hydrolysis and iv) study the chaperone-like properties of DnaX in initiation complex formation.

说明（申请人提供）E.大肠杆菌是典型的复制复合物，表现出与其它细胞复制酶共同的性质，包括高速率的进行性延伸和在复制叉处与其它蛋白质相互作用的能力，建立协调有效染色体复制所需事件所必需的通讯通道。所有细胞复制酶的关键组成部分是同源蛋白质的多亚基组装，其需要ATP将“滑动钳持续合成因子”组装到引物末端。在大肠在大肠杆菌中，该功能由DnaX复合物，DnaX 3 δ Δ ′/khi/psi提供。将E.大肠杆菌编码两种不同的产物：i，全长翻译产物和gamma，一种通过翻译移码产生的较短蛋白质。在下一个资助期内，我们将研究i）DNA聚合酶III全酶的组装途径，重点是Pol III在引导组装途径以允许DnaX亚基的独特排列中的作用，ii）确定在通过DnaX复合物的夹加载器将β 2滑动夹加载到引发的DNA上期间发生的大分子相互作用的变化，iii）确定ATP γ S-辅助的起始复合物形成的机制，其在没有核苷酸水解的情况下进行，和iv）研究DnaX在起始复合物形成中的伴侣样性质。