Site-directed mutagenesis of NnrR: a transcriptional regulator of nitrite and nitric oxide reductase in Rhodobacter sphaeroides.
Site-directed mutagenesis of NnrR: a transcriptional regulator of nitrite and nitric oxide reductase in Rhodobacter sphaeroides.
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DOI：
10.1016/s0378-1097(03)00821-8
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发表时间：
2003-12
影响因子：
2.1
通讯作者：
W. P. Laratta;J. Shapleigh
中科院分区：
文献类型：
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作者：
W. P. Laratta;J. Shapleigh
NnrR是一种转录激活因子，也是CRP/FNR调节家族的成员，负责控制球形红杆菌中许多反硝化基因的表达。NnrR的明显效应是一氧化氮，在它的存在下，NnrR激活了irkgene和enoroperon的表达，分别编码亚硝酸盐还原酶和一氧化氮还原酶。一氧化氮是否直接与NnrR相互作用激活转录尚不清楚。其他反硝化物携带假定的NnrR同源物。为了深入了解NnrR的功能，对一些保守残基进行了诱变。通过监测anirK-lacZfusion的表达来评估这些变化对NnrR功能的影响。通过这种方法，鉴定出了一个从Tyr93到Cys103的区域，该区域包含对NnrR活性至关重要的残基。
NnrR, a transcriptional activator and member of the CRP/FNR family of regulators, is responsible for controlling the expression of a number of denitrification genes inRhodobacter sphaeroides2.4.3. The apparent effector for NnrR is nitric oxide, and in its presence NnrR activates expression of thenirKgene and thenoroperon, encoding nitrite reductase and nitric oxide reductase, respectively. Whether nitric oxide directly interacts with NnrR to activate transcription is unknown. Other denitrifiers carry putative orthologs of NnrR. To gain insight into NnrR function, a number of conserved residues were mutagenized. The impact of these changes on NnrR function was assessed by monitoring expression of anirK-lacZfusion. In this way a region spanning from Tyr93 to Cys103 that contains residues critical for NnrR activity was identified.