Xer recombination in Escherichia coli - Site-specific DNA topoisomerase activity of the XerC and XerD recombinases
Xer recombination in Escherichia coli - Site-specific DNA topoisomerase activity of the XerC and XerD recombinases
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DOI：
10.1074/jbc.272.35.21927
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发表时间：
1997-08-29
影响因子：
4.8
通讯作者：
Sherratt, DJ
中科院分区：
文献类型：
--
作者：
Cornet, F;Hallet, B;Sherratt, DJ
Xer位点特异性重组在维持大肠杆菌中单体状态下的环状复制中的作用。噬菌体A整合酶家族的两个重组酶XerC和XerD是在染色体位置dif和一系列质粒携带的位置进行重组所必需的。XER重组核心区包含每个重组酶的11个碱基对结合位点，由6到8个碱基对中心区隔开。我们报道，XerC和XerD都是通过松弛含有dif位点的超螺旋质粒而起到位点特异性的I型拓扑异构酶的作用。XerC或XerD的松弛发生在没有配对重组酶的情况下，并且只需要一个重组核心位点，XerC或XerD的松弛活性可以通过添加配对重组酶来完全抑制，前提是存在抑制配对的DNA识别序列。
Xer site-specific recombination functions in maintaining circular replicons in the monomeric state in Escherichia coli. Two recombinases of the bacteriophage A integrase family, XerC and XerD, are required for recombination at the chromosomal site, dif, and at a range of plasmid-borne sites. Xer recombination core sites contain the 11-base pair binding sites for each recombinase separated by a 6 to 8-base pair central region. We report that both XerC and XerD act as site-specific type I topoisomerases by relaxing supercoiled plasmids containing a dif site. Relaxation by either XerC or XerD occurs in the absence of the partner recombinase and requires only a single recombination core site, XerC or XerD relaxation activities are completely inhibited by the addition of the partner recombinase, providing that the DNA recognition sequence for the inhibiting partner is present.