A PERFECTLY SYMMETRIC LAC OPERATOR BINDS THE LAC REPRESSOR VERY TIGHTLY
A PERFECTLY SYMMETRIC LAC OPERATOR BINDS THE LAC REPRESSOR VERY TIGHTLY
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DOI：
10.1073/pnas.80.22.6785
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发表时间：
1983-01-01
期刊：
影响因子：
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通讯作者：
BETZ, JL
中科院分区：
文献类型：
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作者：
SADLER, JR;SASMOR, H;BETZ, JL
构建了一个完全对称的DNA片段，它与大肠杆菌的乳糖抑制物结合得比天然乳糖操纵子序列紧密10倍。这个紧密结合的操作符是自然操作符序列左半部分15个碱基对片段的反向重复。阻遏物对这个对称序列亲和力的增加支持四聚体阻遏物是为与DNA结合的2-模块而设计的，可能是通过2个(或2对)相同的亚基。自然操作符显然是有缺陷的，因为右操作符一半中的错误碱基对，以及操作符两半之间关于最大抑制物结合的不正确间距。
A completely symmetric DNA segment was constructed that binds the lactose repressor of Escherichia coli 10-fold more tightly than does the natural lactose operator sequence. This tight-binding operator is an inverted repeat of a 15-base-pair segment from the left half of the natural operator sequence. The increased affinity of repressor for this symmetric sequence supports the idea that the tetrameric repressor is designed for a 2-module binding to DNA, presumably via 2 (or 2 pairs) of its identical subunits. The natural operator is apparently flawed by incorrect base pairs in the right operator half and by an incorrect spacing between the operator halves with respect to maximal repressor binding.