OSMOTIC CONTROL OF KDP OPERON EXPRESSION IN ESCHERICHIA-COLI
OSMOTIC CONTROL OF KDP OPERON EXPRESSION IN ESCHERICHIA-COLI
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DOI：
10.1073/pnas.78.1.464
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发表时间：
1981-01-01
期刊：
影响因子：
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通讯作者：
EPSTEIN, W
中科院分区：
文献类型：
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作者：
LAIMINS, LA;RHOADS, DB;EPSTEIN, W
在大肠杆菌中，膨压（跨内膜渗透压的差异）调节kdp操纵子的表达。杆菌kdp操纵子编码Kdp，Kdp是一种高亲和力的抑制性转运系统，用于摄取K+。在菌株中研究了Kdp表达的调节，其中β-将半乳糖苷酶lacZ置于kdp启动子的控制下。无论是内部还是外部K+浓度直接控制Kdp的表达。只有当外部K+浓度降低到限制生长的点时，kdp操纵子才表达。增加外部渗透压在恒定的K+浓度，一个程序，降低膨压，引起表达的kdp操纵子。随着渗透位移的幅度增加，对应于膨压的更大降低，Kdp表达的量也增加。因此，kdp操纵子似乎是由一种物理力（膨压）的变化控制的。
Turgor pressure, the difference in osmotic pressure across the inner membrane, regulates expression of the kdp operon in E. coli. The kdp operon codes for Kdp, a high-affinity repressible transport system for the uptake of K+. The regulation of Kdp expression was studied in a strain in which the gene for .beta.-galactosidase, lacZ, was placed under control of the kdp promoter. Neither internal nor external K+ concentrations directly controlled Kdp expression. Only when the external K+ concentration was reduced to the point of limiting growth was the kdp operon expressed. An increase in external osmolarity at constant K+ concentration, a procedure that reduces turgor pressure, caused expression of the kdp operon. As the magnitude of the osmotic shift was increased, corresponding to greater decreases in turgor pressure, the amount of Kdp expression also increased. The kdp operon thus appears to be controlled by changes in a physical force, the turgor pressure.