MUTATIONS THAT ALTER THE ABILITY OF THE ESCHERICHIA-COLI CYCLIC-AMP RECEPTOR PROTEIN TO ACTIVATE TRANSCRIPTION
MUTATIONS THAT ALTER THE ABILITY OF THE ESCHERICHIA-COLI CYCLIC-AMP RECEPTOR PROTEIN TO ACTIVATE TRANSCRIPTION
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DOI：
10.1093/nar/18.24.7243
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发表时间：
1990-12-25
影响因子：
14.9
通讯作者：
BUSBY, S
中科院分区：
文献类型：
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作者：
BELL, A;GASTON, K;BUSBY, S
研究了E.大肠杆菌环腺苷酸受体蛋白（CRP）已被确定通过监测在体内表达和体外开放复合物的形成在两个半合成的启动子，是完全CRP依赖。 在一个启动子处，CRP结合位点集中在转录起始点上游约41.5个碱基对处，而在另一个启动子处，它位于上游61.5个碱基对处。 CRP突变E171 K降低了两种启动子的表达，而H159 L使CRP完全失活：突变K52 N和K52 Q都不能逆转H159 L的作用，也不能“再教育”CRP以激活转录。 携带H159 L和K52 N两者的CRP比野生型CRP更好地激活从CRP位点在-41.5处的启动子的转录。 与此形成鲜明对比的是，这种双重改变的CRP对于从携带CRP位点在-61.5的启动子转录的激活是完全无活性的。 我们的研究结果表明，CRP可以使用不同的接触和/或构象在转录激活过程中在不同的架构启动子。
The effects of a number of mutations in the E. coli cyclic AMP receptor protein (CRP) have been determined by monitoring the in vivo expression and in vitro open complex formation at two semi-synthetic promoters that are totally CRP-dependent. At one promoter the CRP-binding site is centred around 41.5 base pairs upstream from the transcription start whilst at the other promoter it is 61.5 base pairs upstream. The CRP mutation E171K reduces expression from both promoters whilst H159L renders CRP totally inactive: neither mutations K52N and K52Q reverse the effect of H159L and 'reeducate' CRP to activate transcription. CRP carrying both H159L and K52N activates transcription from the promoter with the CRP site at -41.5 better than wild type CRP. In sharp contrast, this doubly changed CRP is totally inactive with respect to the activation of transcription from the promoter carrying the CRP site at -61.5. Our results suggest that CRP can use different contacts and/or conformations during transcription activation at promoters with different architectures.