Marszalek J, Kaguni J M
Department of Biochemistry, Michigan State University, East Lansing 48824-1319.
J Biol Chem. 1994 Feb 18;269(7):4883-90.
DnaA protein of Escherichia coli acts in the initiation of chromosomal replication to bind to sequences in the chromosomal origin. On binding, it promotes the assembly of other replication proteins that serve to prime DNA replication and assemble the replication apparatus for bidirectional replication fork movement. A collection of monoclonal antibodies to DnaA protein have been produced, one of which is described here, that interferes with the action of DnaA protein in promoting formation of a prepriming complex. On the analysis of this process, the antibody appears to interfere with the physical interaction between DnaA and DnaB protein in the DnaB.DnaC complex. Cross-linking studies confirm that DnaA and DnaB proteins interact directly. These results provide the first direct evidence that one of the roles of DnaA protein is to act as a site for binding of DnaB protein to the DNA and perhaps orients DnaB helicase to account for the directionality of replication fork movement.
大肠杆菌的DnaA蛋白在染色体复制起始过程中发挥作用，与染色体起源处的序列结合。结合后，它促进其他复制蛋白的组装，这些蛋白用于引发DNA复制并组装复制装置以进行双向复制叉移动。已经产生了一系列针对DnaA蛋白的单克隆抗体，这里描述了其中一种，它干扰DnaA蛋白在促进引发前复合物形成中的作用。在对这个过程的分析中，该抗体似乎干扰了DnaB.DnaC复合物中DnaA与DnaB蛋白之间的物理相互作用。交联研究证实DnaA和DnaB蛋白直接相互作用。这些结果提供了第一个直接证据，表明DnaA蛋白的作用之一是作为DnaB蛋白与DNA结合的位点，并且可能使DnaB解旋酶定向以解释复制叉移动的方向性。
