OXYR, A POSITIVE REGULATOR OF HYDROGEN PEROXIDE-INDUCIBLE GENES IN ESCHERICHIA-COLI AND SALMONELLA-TYPHIMURIUM, IS HOMOLOGOUS TO A FAMILY OF BACTERIAL REGULATORY PROTEINS
OXYR, A POSITIVE REGULATOR OF HYDROGEN PEROXIDE-INDUCIBLE GENES IN ESCHERICHIA-COLI AND SALMONELLA-TYPHIMURIUM, IS HOMOLOGOUS TO A FAMILY OF BACTERIAL REGULATORY PROTEINS
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DOI：
10.1073/pnas.86.10.3484
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发表时间：
1989-05-01
影响因子：
11.1
通讯作者：
AMES, BN
中科院分区：
文献类型：
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作者：
CHRISTMAN, MF;STORZ, G;AMES, BN
OXR基因是在大肠杆菌和鼠伤寒沙门氏菌中诱导过氧化氢诱导基因的调节子所必需的。我们已经克隆并测序了E.ColioxR基因，发现了一个开放阅读框(305个氨基酸)，它编码一个34.4 kDa的蛋白质，该蛋白质在携带OxR克隆的最大细胞中产生。OxyR蛋白与一系列阳性调控蛋白同源，包括大肠杆菌中的LysR和根瘤菌中的Nodd。与它们一样，OxyR似乎是负自我调节的：Ox R：：LacZ基因融合在Ox R缺失突变体中产生的β-半乳糖苷酶活性是Ox R+对照的5倍，并且OxyR高产菌株的提取物能够保护Ox R启动子的-27至+21区域免受DNase I的消化。对OxyR2突变的DNA序列分析表明，OxyR2的表型是由于错义突变(C.cntdot.G到T.cntdot.A转换)造成的，该突变将OxyR的第234位氨基酸的丙氨酸改变为Valine。
The oxyR gene is required for the induction of a regulon of hydrogen peroxide-inducible genes in Escherichia coli and Salmonella typhimurium. The E. coli oxyR gene has been cloned and sequenced, revealing an open reading frame (305 amino acids) that encodes a 34.4-kDa protein, which is produced in maxicells carrying the oxyR clone. The OxyR protein shows homology to a family of positive regulatory proteins including LysR in E. coli and NodD in Rhizobium. Like them, oxyR appears to be negatively autoregulated: an oxyR::lacZ gene fusion produced 5-fold higher levels of .beta.-galactosidase activity in oxyR null mutants compared to oxyR+ controls, and extracts from an OxyR-overproducing strain were able to protect regions (-27 to +21) of the oxyR promoter from DNase I digestion. DNA sequence analysis of the oxyR2 mutation, which causes overexpression of OxyR-regulated proteins in the absence of oxidative stress, showed that the oxyR2 phenotype is due to a missense mutation (C.cntdot.G to T.cntdot.A transition) that changes alanine to valine at amino acid position 234 of OxyR.