Young B S, Guterman S K, Wright A
J Bacteriol. 1976 Sep;127(3):1292-7. doi: 10.1128/jb.127.3.1292-1297.1976.
Localized mutagenes of Salmonella typhimurium followed by a [3H]uridine enrichment procedure yielded a temperature-sensitive strain with a mutation in the rpo region of the chromosome. Ribonucleic acid (RNA) polymerase (EC 2.7.7.6; nucleoside triphosphate: RNA nucleotidyltransferase) purified from this mutant was considerably less active at the nonpermissive temperature than wild-type enzyme. Furthermore, the enzyme from this mutant, unlike RNA polymerase of previously isolated temperature-sensitive mutants, was as thermostable as wild-type enzyme when preincubated at 50 degrees C. Subunit reconstitution experiments have shown that the temperature sensitivity is caused by an alteration in the beta' subunit of the enzyme.
对鼠伤寒沙门氏菌进行局部诱变,随后采用[3H]尿苷富集程序,得到了一株在染色体rpo区域发生突变的温度敏感型菌株。从该突变体中纯化的核糖核酸(RNA)聚合酶(EC 2.7.7.6;核苷三磷酸:RNA核苷酸转移酶)在非允许温度下的活性比野生型酶低得多。此外,与先前分离的温度敏感型突变体的RNA聚合酶不同,该突变体的酶在50℃预孵育时与野生型酶一样耐热。亚基重组实验表明,温度敏感性是由该酶β'亚基的改变引起的。