Spacer mutations in the lac ps promoter.
Spacer mutations in the lac ps promoter.
复制标题
lac ps 启动子中的间隔突变。
DOI：
10.1073/pnas.79.4.1069
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发表时间：
1982
影响因子：
11.1
通讯作者：
Gralla,JD
中科院分区：
文献类型：
--
作者：
Stefano,JE;Gralla,JD
已经构建了缺失lac ps启动子中位置-19附近的一个或两个碱基对的突变。两个相邻碱基对中的任何一个的缺失使开放复合物形成的速率增加了近一个数量级。具有不同的单碱基缺失的两个启动子通过它们的开放复合物形成的速率或一旦形成的开放复合物的稳定性是不可区分的。然而，同时缺失两个碱基对会产生一个启动子，该启动子以与未修饰的DNA序列相似的速率形成复合物。开放复合物形成的最大速率在17个碱基对的间隔区长度下实现，这是启动子中最常见的间隔区长度。这些结果表明，序列同源性的两个强保守区域之间的间距是开放复合物形成速率的重要决定因素。一个模型建议，提出了三个重要的启动子元件，-10区域，-35区域，和间隔区，同时采取行动，以促进开放的复合物形成的RNA聚合酶。
Mutations have been constructed that delete either one or two base pairs near position -19 in the lac ps promoter. Deletion of either of two adjacent base pairs increases the rates of open complex formation by nearly on order of magnitude. Two promoters that have different single-base deletions are indistinguishable by either their rates of open complex formation or stability of the open complexes once formed. However, simultaneous deletion of both base pairs produces a promoter that forms complexes at a rate similar to that of the unmodified DNA sequence. The maximal rate of open complex formation is achieved at a spacer length of 17 base pairs, the most frequently occurring spacer length among promoters. These results suggest that the spacing between the two strongly conserved regions of sequence homology is an important determinant of the rate of open complex formation. A model is suggested that proposes that three important promoter elements, the -10 region, the -35 region, and the spacer region, act simultaneously to facilitate open complex formation by RNA polymerase.