Crystal structure of a prokaryotic replication initiator protein bound to DNA at 2.6 Å resolution
Crystal structure of a prokaryotic replication initiator protein bound to DNA at 2.6 Å resolution
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DOI：
10.1093/emboj/18.17.4597
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发表时间：
1999-09-01
期刊：
影响因子：
11.4
通讯作者：
Miki, K
中科院分区：
文献类型：
--
作者：
Komori, H;Matsunaga, F;Miki, K
F因子的起始蛋白（Initiator protein，RepE）是大肠杆菌中参与有性接合的质粒，在DNA复制起始过程中具有双重功能，其功能取决于RepE单体或二聚体的存在形式。RepE单体作为复制起始子，RepE二聚体作为自身阻遏子。我们已经解决了RepE单体的晶体结构结合到一个iteron DNA序列的复制起点的质粒F。RepE单体由拓扑结构相似的N-和C-末端结构域组成，它们通过内部假2重对称性彼此相关，尽管结构域之间缺乏氨基酸相似性。这两个结构域以不同的结合亲和力结合到iteron的两个主要凹槽（19 bp）。C-末端结构域在这种结合中起主导作用，而N-末端结构域在RepE二聚化中具有额外的作用。该结构还表明，由四个RepE和一个HU二聚体在质粒F的起点处诱导的超螺旋DNA在DNA复制的起始中具有重要作用。
The initiator protein (RepE) of F factor, a plasmid involved in sexual conjugation in Escherichia coli, has dual functions during the initiation of DNA replication which are determined by whether it exists as a dimer or as a monomer, A RepE monomer functions as a replication initiator, but a RepE dimer functions as an autogenous repressor. We have solved the crystal structure of the RepE monomer bound to an iteron DNA sequence of the replication origin of plasmid F. The RepE monomer consists of topologically similar N- and C-terminal domains related to each other by internal pseudo 2-fold symmetry, despite the lack of amino acid similarities between the domains. Both domains bind to the two major grooves of the iteron (19 bp) with different binding affinities. The C-terminal domain plays the leading role in this binding, while the N-terminal domain has an additional role in RepE dimerization, The structure also suggests that superhelical DNA induced at the origin of plasmid F by four RepEs and one HU dimer has an essential role in the initiation of DNA replication.