A DNA region recognized by the nitric oxide-responsive transcriptional activator NorR is conserved in β- and γ-proteobacteria
A DNA region recognized by the nitric oxide-responsive transcriptional activator NorR is conserved in β- and γ-proteobacteria
复制标题
DOI：
10.1128/jb.186.23.7980-7987.2004
复制
发表时间：
2004-12-01
影响因子：
3.2
通讯作者：
Cramm, R
中科院分区：
文献类型：
--
作者：
Büsch, A;Pohlmann, A;Cramm, R
sigma（54）依赖性调节因子NorR激活靶基因的转录，以响应一氧化氮（NO）或NO生成剂。在富营养化拉尔夫氏菌H16中，NorR激活双双子norAB操纵子的转录，该操纵子编码功能未知的蛋白质NorA和一氧化氮还原酶NorB。凝胶阻滞分析显示，一种组成性激活的NorR衍生物（NorR'），其n端信号域被MalE取代，特异性结合到norAB上游区域。在DNase I足迹测定中，在一个由mai - norr '保护的73bp DNA片段中，我们鉴定了三个保守的反向重复序列GGT-(N-7)- acc（其中N是任意碱基），我们认为它们是norr结合盒。突变改变了这些重复序列的间距或碱基序列，导致野生型NorR的转录激活降低了80%至90%。基因组数据库分析表明，该反向重复序列的GT-(N-7)- ac核心存在于几种编码一氧化氮代谢蛋白的基因位点上游的proteobacteria中，包括一氧化氮还原酶（NorB）、flavorubredoxin （NorV）、NO双加氧酶（Hmp）和杂交簇蛋白（Hcp）。
The sigma(54)-dependent regulator NorR activates transcription of target genes in response to nitric oxide (NO) or NO-generating agents. In Ralstonia eutropha H16, NorR activates transcription of the dicistronic norAB operon that encodes NorA, a protein of unknown function, and NorB, a nitric oxide reductase. A constitutively activating NorR derivative (NorR'), in which the N-terminal signaling domain was replaced by MalE, specifically bound to the norAB upstream region as revealed by gel retardation analysis. Within a 73-bp DNA segment protected by MaIE-NorR' in a DNase I footprint assay, three conserved inverted repeats, GGT-(N-7)-ACC (where N is any base), that we consider to be NorR-binding boxes were identified. Mutations altering the spacing or the base sequence of these repeats resulted in an 80 to 90% decrease of transcriptional activation by wildtype NorR. Genome database analyses demonstrate that the GT-(N-7)-AC core of the inverted repeat is found in several proteobacteria upstream of gene loci encoding proteins of nitric oxide metabolism, including nitric oxide reductase (NorB), flavorubredoxin (NorV), NO dioxygenase (Hmp), and hybrid cluster protein (Hcp).