Structural analysis of the ParR/parC plasmid partition complex
Structural analysis of the ParR/parC plasmid partition complex
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DOI：
10.1038/sj.emboj.7601864
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发表时间：
2007-10-17
期刊：
影响因子：
11.4
通讯作者：
Loewe, Jan
中科院分区：
文献类型：
--
作者：
Moller-Jensen, Jakob;Ringgaard, Simon;Loewe, Jan
细胞分裂时DNA的准确分配对所有生物体都至关重要。在细菌中，这一过程可能涉及染色体和质粒上的分配位点。大肠杆菌质粒R1分配的初始步骤涉及DNA结合蛋白ParR和其在DNA上的同源着丝粒位点parC之间的分配复合物的形成。该分区复合物被第二个分区蛋白--肌动蛋白样ATP酶ParM识别，该蛋白形成DNA复制的主动双向运动所需的细丝。本文报道了E. coli质粒pB 171。ParR形成紧密的二聚体，类似于二聚体带-螺旋-螺旋（RHH）2位点特异性DNA结合蛋白的大家族。晶体学和电子显微镜数据进一步表明，ParR二聚体组装成一个螺旋结构，DNA结合位点朝外。遗传和生物化学实验支持这样一种结构安排，即着丝粒样parC DNA包裹在ParR蛋白支架周围。这种结构对ParM聚合如何在质粒分配期间驱动主动DNA转运具有影响。
Accurate DNA partition at cell division is vital to all living organisms. In bacteria, this process can involve partition loci, which are found on both chromosomes and plasmids. The initial step in Escherichia coli plasmid R1 partition involves the formation of a partition complex between the DNA-binding protein ParR and its cognate centromere site parC on the DNA. The partition complex is recognized by a second partition protein, the actin-like ATPase ParM, which forms filaments required for the active bidirectional movement of DNA replicates. Here, we present the 2.8A crystal structure of ParR from E. coli plasmid pB171. ParR forms a tight dimer resembling a large family of dimeric ribbon-helix-helix (RHH) 2 site-specific DNA-binding proteins. Crystallographic and electron microscopic data further indicate that ParR dimers assemble into a helix structure with DNA-binding sites facing outward. Genetic and biochemical experiments support a structural arrangement in which the centromere-like parC DNA is wrapped around a ParR protein scaffold. This structure holds implications for how ParM polymerization drives active DNA transport during plasmid partition.