Isolation and characterization of a new globomycin-resistant dnaE mutant of Escherichia coli.
Isolation and characterization of a new globomycin-resistant dnaE mutant of Escherichia coli.
复制标题
大肠杆菌新的球霉素抗性 dnaE 突变体的分离和表征。
DOI：
10.1128/jb.169.8.3400-3408.1987
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发表时间：
1987
影响因子：
3.2
通讯作者：
Wu,HC
中科院分区：
文献类型：
--
作者：
Sakka,K;Watanabe,T;Beers,R;Wu,HC
我们从大肠杆菌K-12菌株AB 1157中分离出一株对球霉素具有抗性、温度敏感的突变株。该突变定位在DNA聚合酶III α亚基的结构基因dnaE中。在体内加工的脂质修饰的前脂蛋白是更耐球霉素的突变株307比其亲本。前脂蛋白信号肽酶的活性也增加了两倍的突变体，并有一个异亮氨酰-tRNA合成酶的活性增加了三倍。结果提示，dnaE基因突变可能影响了ileS-lsp操纵子在大肠杆菌中的表达。杆菌此外，菌株307与其亲本菌株AB 1157（rpsL 31）相比显示出降低的链霉素抗性水平。菌株307被浓度为200 μ g/ml的链霉素杀死，这不影响该突变体中大量蛋白质合成的速率。第二个突变，这是在减少链霉素耐药性菌株307被确定，并发现密切相关的rpsD（拉马，核糖体模糊性）基因或内。dnaE和rpsD都是307菌株链霉素抗性降低所必需的。
We isolated a globomycin-resistant, temperature-sensitive mutant of Escherichia coli K-12 strain AB1157. The mutation mapped in dnaE, the structural gene for the alpha-subunit of DNA polymerase III. The in vivo processing of lipid-modified prolipoprotein was more resistant to globomycin in the mutant strain 307 than in its parent. The prolipoprotein signal peptidase activity was also increased twofold in the mutant, and there was a threefold increase in the activity of isoleucyl-tRNA synthetase. The results suggest that a mutation in dnaE may affect the expression of the ileS-lsp operon in E. coli. In addition, strain 307 showed a reduced level of streptomycin resistance compared with its parental strain AB1157 (rpsL31). Strain 307 was killed by streptomycin at a concentration of 200 micrograms/ml, which did not affect the rate of bulk protein synthesis in this mutant. A second mutation which was involved in the reduced streptomycin resistance in strain 307 was identified and found to be closely linked to or within the rpsD (ramA, ribosomal ambiguity) gene. Both dnaE and rpsD were required for the reduced streptomycin resistance in strain 307.