通过跨主导RNA聚合酶突变阻断启动到延长的过渡
M Kashlev1, J Lee, K Zalenskaya
1Institute of Molecular Genetics, U.S.S.R. Academy of Sciences, Moscow.
概括
大肠杆菌RNA聚合酶中的突变通过防止DNA延长来破坏基因表达. 这种突变酶抑制细胞生长,并阻止野生型聚合酶进入促进体.
科学领域:
- 分子生物学分子生物学
- 酶学 是一种酶学.
- 遗传学 遗传学 是一个
背景情况:
- RNA聚合酶对于基因表达至关重要,具有保存的结构特征.
- RNA聚合酶的β子单元在其催化功能中起着至关重要的作用.
研究的目的:
- 为了研究进化不变的氨基酸替代 (Lys1065Arg) 在大肠杆菌RNA聚合酶β子单元中的功能影响.
- 确定这种突变如何影响RNA聚合酶活性,细胞生长和转录.
主要方法:
- 局部导向的突变发生引入E. coliRNA聚合酶β子单元中的Lys1065Arg替代.
- 突变RNA聚合酶从可诱导促进体的表达.
- 对全酶组合,促进体复合体形成,二核酸合成和转录延长的分析.
- 评估突变聚合酶对细胞生长和野生类型酶活性的影响.
主要成果:
- 在β子单元中的Lys1065Arg替代破坏了RNA聚合酶的催化中心.
- 突变蛋白的表达抑制了细胞生长.
- 突变的全酶形成了稳定的促进体复合物和合成的二核酸,但未能启动延长.
- 突变的聚合酶通过阻止野生型RNA聚合酶进入促进体来抑制转录.
结论:
- 在β子单元中的进化不变的Lys1065残留物对RNA聚合酶催化活性和转录延长至关重要.
- 这种残留物的破坏会产生主要的负面效应,抑制突变和野生型聚合酶的功能,并影响细胞活力.
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