Hessing H G, van Rotterdam C, Pouwels P H
Medical Biological Laboratory TNO, Rijswijk, The Netherlands.
Mol Gen Genet. 1987 Dec;210(2):256-61. doi: 10.1007/BF00325691.
We have investigated the effect of alterations in the structure of the plasmid-borne Escherichia coli tryptophan (trp) coding region and other regions of the same replicon on the level, rate and time of initiation of anthranilate synthetase component I (ASase) synthesis in E. coli K12. The maximum level of ASase produced corresponds to 60%-65% of the total cellular proteins. Adding sequences downstream of the trpE coding region decreases the level but does not affect the time of initiation and rate of trpE expression (ASase synthesis). The presence of additional protein coding sequences on the plasmid outside the trpE-A region causes ASase production to start earlier and decreases the rate of ASase synthesis. A second copy of the trpE coding sequences, if present within or outside the trpE-A coding region on the same replicon, doubles the rate of synthesis of ASase and slightly increases its final level of production. The initiation of ASase production occurs earlier when the two trpE copies are located within two distinct transcription units.
我们研究了质粒携带的大肠杆菌色氨酸（trp）编码区及同一复制子其他区域结构的改变对大肠杆菌K12中邻氨基苯甲酸合成酶组分I（ASase）合成的起始水平、速率和时间的影响。所产生的ASase的最大水平相当于细胞总蛋白的60% - 65%。在trpE编码区下游添加序列会降低水平，但不影响trpE表达（ASase合成）的起始时间和速率。trpE - A区域外的质粒上存在额外的蛋白质编码序列会使ASase产生更早开始，并降低ASase合成速率。如果trpE编码序列的第二个拷贝存在于同一复制子的trpE - A编码区内或区外，ASase的合成速率会加倍，并略微提高其最终产生水平。当两个trpE拷贝位于两个不同的转录单元中时，ASase产生的起始会更早发生。
