Liberek K, Osipiuk J, Zylicz M, Ang D, Skorko J, Georgopoulos C
Department of Molecular Biology, University of Gdansk, Poland.
J Biol Chem. 1990 Feb 25;265(6):3022-9.
The process of initiation of lambda DNA replication requires the assembly of the proper nucleoprotein complex at the origin of replication, ori lambda. The complex is composed of both phage and host-coded proteins. The lambda O initiator protein binds specifically to ori lambda. The lambda P initiator protein binds to both lambda O and the host-coded dnaB helicase, giving rise to an ori lambda DNA.lambda O.lambda P.dnaB structure. The dnaK and dnaJ heat shock proteins have been shown capable of dissociating this complex. The thus freed dnaB helicase unwinds the duplex DNA template at the replication fork. In this report, through cross-linking, size chromatography, and protein affinity chromatography, we document some of the protein-protein interactions occurring at ori lambda. Our results show that the dnaK protein specifically interacts with both lambda O and lambda P, and that the dnaJ protein specifically interacts with the dnaB helicase.
λ噬菌体DNA复制起始过程需要在复制起点ori λ处组装合适的核蛋白复合物。该复合物由噬菌体和宿主编码的蛋白质组成。λ噬菌体O起始蛋白特异性结合ori λ。λ噬菌体P起始蛋白与λ噬菌体O和宿主编码的dnaB解旋酶结合，形成ori λ DNA·λ噬菌体O·λ噬菌体P·dnaB结构。已证明dnaK和dnaJ热休克蛋白能够解离该复合物。由此释放的dnaB解旋酶在复制叉处解开双链DNA模板。在本报告中，通过交联、尺寸排阻色谱和蛋白质亲和色谱，我们记录了在ori λ处发生的一些蛋白质-蛋白质相互作用。我们的结果表明，dnaK蛋白特异性地与λ噬菌体O和λ噬菌体P相互作用，而dnaJ蛋白特异性地与dnaB解旋酶相互作用。
