Kölling R, Lother H
J Bacteriol. 1985 Oct;164(1):310-5. doi: 10.1128/jb.164.1.310-315.1985.
The regulation of the asparagine synthetase A gene of Escherichia coli was studied in vitro with a coupled transcription-translation system. It was shown that the 17-kilodalton gene, which is transcribed divergently from the adjacent asnA gene, codes for an activator of asnA transcription. The synthesis of the 17-kilodalton protein, which we now call AsnC, is autogenously regulated. The stimulating effect of AsnC on asnA transcription is abolished by asparagine, while the autoregulation of asnC is not affected by asparagine. The N-terminal part of the asnC protein, inferred from the DNA sequence, is homologous to the DNA-binding domain of regulatory proteins like catabolite gene activator, cro, and cI. This homology and direct repeats found in the region of the two asn promoters suggest that the asnC protein regulates transcription by binding to DNA. The asn promoters were defined by mapping of the mRNA start sites of in vitro-generated transcripts.
利用偶联转录-翻译系统在体外研究了大肠杆菌天冬酰胺合成酶A基因的调控。结果表明，与相邻的天冬酰胺合成酶A基因反向转录的17千道尔顿基因编码天冬酰胺合成酶A转录的激活剂。我们现在称为天冬酰胺C的17千道尔顿蛋白质的合成是自动调控的。天冬酰胺可消除天冬酰胺C对天冬酰胺合成酶A转录的刺激作用，而天冬酰胺对天冬酰胺C的自身调控没有影响。根据DNA序列推断，天冬酰胺C蛋白质的N端部分与分解代谢基因激活剂、cro和cI等调控蛋白的DNA结合结构域同源。在两个天冬酰胺启动子区域发现的这种同源性和直接重复序列表明，天冬酰胺C蛋白质通过与DNA结合来调控转录。通过对体外转录本的mRNA起始位点进行定位确定了天冬酰胺启动子。
