THE GLOBAL REGULATORY PROTEIN FRUR MODULATES THE DIRECTION OF CARBON FLOW IN ESCHERICHIA-COLI
THE GLOBAL REGULATORY PROTEIN FRUR MODULATES THE DIRECTION OF CARBON FLOW IN ESCHERICHIA-COLI
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DOI：
10.1111/j.1365-2958.1995.tb02339.x
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发表时间：
1995-06-01
影响因子：
3.6
通讯作者：
SAIER, MH
中科院分区：
文献类型：
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作者：
RAMSEIER, TM;BLEDIG, S;SAIER, MH
大肠杆菌果糖阻遏蛋白FruR是一种调节碳源利用相关基因表达的蛋白质。使用先前推导的FruR结合的共有序列，鉴定了另外的潜在操作者，并在DNA条带迁移阻滞测定中测试了FruR结合。与碳代谢相关的操纵子控制区中的操纵子与FruR结合，而与碳代谢无关的操纵子中的操纵子则不结合。在体内试验与转录lacZ融合表明，FruR控制表达的FruR操纵基因编码的关键酶，几乎每一个主要的碳代谢途径。此外，fruR无效突变改变了至少36种碳源的利用率。在一般情况下，糖酵解物质的氧化速率提高，而那些产酶物质被压抑。FruR算子的比对显示，FruR结合的共有序列对于被FruR激活和抑制的操纵子是相同的，并且允许制定经修订的FruR结合共有序列。报告的观察结果表明，FruR调节碳流的方向，通过转录激活的基因编码的酶有关的氧化和产气碳流和抑制那些有关的发酵碳流。
Escherichia coli fructose repressor, FruR, is known to regulate expression of several genes concerned with carbon utilization. Using a previously derived consensus sequence for FruR binding, additional potential operators were identified and tested for FruR binding in DNA band migration retardation assays. Operators in the control regions of operons concerned with carbon metabolism bound FruR, while those in operons not concerned with carbon metabolism did not. In vivo assays with transcriptional lacZ fusions showed that FruR controls the expression of FruR operator-containing genes encoding key enzymes of virtually every major pathway of carbon metabolism. Moreover, a fruR null mutation altered the rates of utilization of at least 36 carbon sources. In general, oxidation rates for glycolytic substances were enhanced while those for gluconeogenic substances were depressed. Alignment of FruR operators revealed that the consensus sequence for FruR binding is the same for operons that are activated and repressed by FruR and permitted formulation of a revised FruR-binding consensus sequence. The reported observations indicate that FruR modulates the direction of carbon flow by transcriptional activation of genes encoding enzymes concerned with oxidative and gluconeogenic carbon flow and by repression of those concerned with fermentative carbon flow.