Characterization of Polynucleotide Phosphorylase Mutants of Escherichia coli
Characterization of Polynucleotide Phosphorylase Mutants of Escherichia coli
复制标题
大肠杆菌多核苷酸磷酸化酶突变体的表征
DOI：
10.1128/jb.97.3.1437-1443.1969
复制
发表时间：
1969
影响因子：
3.2
通讯作者：
A. Reiner
中科院分区：
文献类型：
--
作者：
A. Reiner
从高度诱变的大肠杆菌菌株Q7、Q13和Q27中分离到三个多核苷酸磷酸化酶突变，通过P1转导到缺乏核糖核酸酶I的近等基因菌株后，对它们进行了鉴定。每个菌株都有不同的多核苷酸磷酸化酶改变形式。在所有测试条件下，有一种酶的活性急剧下降。第二种酶的活性降低，这是由Mn++刺激的。第三种酶是不耐热的，如果阻止细胞生长，在44℃和pH 6的条件下可以在体内失活95%；在这些条件和其他条件下的生长过程中，完整的酶水平保持不变。这些菌株的生长速度、对介质和温度变化的适应能力，以及从饥饿中恢复的能力，都与野生株没有区别。
Three polynucleotide phosphorylase mutations, isolated in heavily mutagenized Escherichia coli strains Q7, Q13, and Q27, were characterized after their transfer by P1 transduction to nearly isogenic strains which lack ribonuclease I. Each strain has a different altered form of polynucleotide phosphorylase. One enzyme exhibited sharply reduced activity under all conditions tested. A second had reduced activity which was stimulated by Mn++. The third enzyme was thermolabile and could be >95% inactivated in vivo at 44 C and pH 6 if the cells were prevented from growing; during growth under these and other conditions, the full enzyme level was maintained. The strains showed no differences from the wild type in their growth rates, their adjustments to changes in media and temperature, or their recoveries from starvation.