DEREPRESSION OF ANTHRANILATE SYNTHASE IN PURIFIED MINICELLS OF ESCHERICHIA-COLI CONTAINING COL-TRP PLASMID
DEREPRESSION OF ANTHRANILATE SYNTHASE IN PURIFIED MINICELLS OF ESCHERICHIA-COLI CONTAINING COL-TRP PLASMID
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DOI：
10.1128/jb.115.2.615-622.1973
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发表时间：
1973-01-01
影响因子：
3.2
通讯作者：
CURTISS, R
中科院分区：
文献类型：
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作者：
FRAZER, AC;CURTISS, R
含有质粒 Col-trp+ 或 Col-trpA2 的纯化大肠杆菌 K-12 小细胞可以去抑制邻氨基苯甲酸合成酶的合成，邻氨基苯甲酸合成酶是 thetrpoperon 中编码的第一种酶。不含质粒、脱氧核糖核酸缺陷的小细胞不能被去抑制。色氨酸饥饿引发去抑制的酶合成。用含有 Col-trpA2 质粒的小细胞研究了去抑制动力学。去抑制曲线是双相的，酶合成的初始速率较快，随后合成速率较慢。 1-色氨酸（20 至 50 μg/ml）或氯霉素（200 μg/ml）的存在会破坏酶的合成。暴露至少 3.5 分钟后，利福霉素 SV (280 μg/ml) 的存在会部分抑制酶合成。根据每单位细胞体积的去抑制酶活性进行比较，小细胞与细胞合成能力的比率为 1:2.4。这项工作表明，含有质粒的小细胞能够合成相当多的功能性蛋白质和信使核糖核酸，并且至少thetrpoperon的调节在小细胞中与在细胞中观察到的相似。
Purified minicells ofEscherichia coliK-12 containing the plasmid Col-trp+or Col-trpA2could be derepressed for the synthesis of anthranilate synthase, the first enzyme encoded in thetrpoperon. Non-plasmid-containing, deoxyribonucleic acid-deficient minicells could not be derepressed. Derepressed enzyme synthesis was initiated byl-tryptophan starvation. The kinetics of derepression were studied with minicells containing the Col-trpA2plasmid. The derepression curves were biphasic with a rapid initial rate of enzyme synthesis followed by a slower rate of synthesis. The presence ofl-tryptophan (20 to 50 μg/ml) or chloramphenicol (200 μg/ml) abolished enzyme synthesis. The presence of rifamycin SV (280 μg/ml) partially inhibited enzyme synthesis after at least 3.5 min of exposure. The ratio of minicell-to-cell synthetic capacity was 1:2.4 when compared on the basis of derepressed enzyme activity per unit cell volume. This work demonstrates that plasmid-containing minicells are capable of considerable functional protein and messenger ribonucleic acid synthesis and that the regulation of at least thetrpoperon is similar in minicells to that observed in cells.