Stringent and relaxed recognition of oriT by related systems for plasmid mobilization: implications for horizontal gene transfer.
Stringent and relaxed recognition of oriT by related systems for plasmid mobilization: implications for horizontal gene transfer.
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质粒动员相关系统对 oriT 的严格和宽松识别：对水平基因转移的影响。
DOI：
10.1128/jb.188.2.499-506.2006
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Meyer,Richard
中科院分区：
文献类型：
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作者：
Jandle,Sarah;Meyer,Richard
R1162和pSC101具有密切相关的接合转移(Orits)和相应的松弛酶起源。TheoriT由一个高度保守的核心和一个大小和序列不同的反向重复序列组成，其中DNA在转移之前被松弛酶切割。我们证明，在每种情况下，与核心相邻的七个碱基对和反向重复序列的一条臂内的七个碱基对足以确定特异性。在这个DNA中，有三个AT碱基对，位于距离核心4个碱基对的位置。AT碱基对的突变表明，松弛酶在这些位置与DNA的小沟进行必要的接触。其余四个碱基对于每个T来说是不同的，对于pSC101动员蛋白对IT的严格识别来说既是必要的，也是充分的。相反，R1162动员蛋白对这个特异性区域的碱基序列的要求要宽松得多。因此，R1162动员蛋白可以启动来自各种部位的转移，包括来自染色体的那些部位。因此，R1162动员蛋白可能有助于不同来源的DNA的水平基因转移。
The plasmids R1162 and pSC101 have origins of conjugative transfer (oriTs) and corresponding relaxases that are closely related. TheoriTs are made up of a highly conserved core, where DNA is cleaved by the relaxase prior to transfer, and an inverted repeat that differs in size and sequence. We show that in each case the seven base pairs adjacent to the core and within one arm of the inverted repeat are sufficient to determine specificity. Within this DNA there are three AT base pairs located 4 bp from the core. Mutations in the AT base pairs suggest that the relaxase makes essential contacts at these locations to the minor groove of the DNA. The remaining four bases are different for eachoriTand are both necessary and sufficient for stringent recognition oforiTby the pSC101 mobilization proteins. In contrast, the R1162 mobilization proteins have a much more relaxed requirement for the base sequence of this specificity region. As a result, the R1162 mobilization proteins can initiate transfer from a variety of sites, including those derived from the chromosome. The R1162 mobilization proteins could therefore contribute to the horizontal gene transfer of DNA from diverse sources.