Buck Amy H, Dalby Andrew B, Poole Alexander W, Kazantsev Alexei V, Pace Norman R
Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA.
EMBO J. 2005 Oct 5;24(19):3360-8. doi: 10.1038/sj.emboj.7600805. Epub 2005 Sep 15.
Bacterial ribonuclease P (RNase P) belongs to a class of enzymes that utilize both RNAs and proteins to perform essential cellular functions. The bacterial RNase P protein is required to activate bacterial RNase P RNA in vivo, but previous studies have yielded contradictory conclusions regarding its specific functions. Here, we use biochemical and biophysical techniques to examine all of the proposed functions of the protein in both Escherichia coli and Bacillus subtilis RNase P. We demonstrate that the E. coli protein, but not the B. subtilis protein, stabilizes the global structure of RNase P RNA, although both proteins influence holoenzyme dimer formation and precursor tRNA recognition to different extents. By comparing each protein in complex with its cognate and noncognate RNA, we show that differences between the two types of holoenzymes reside primarily in the RNA and not the protein components of each. Our results reconcile previous contradictory conclusions regarding the role of the protein and support a model where the protein activates local RNA structures that manifest multiple holoenzyme properties.
细菌核糖核酸酶P（RNase P）属于一类利用RNA和蛋白质来执行基本细胞功能的酶。细菌RNase P蛋白在体内是激活细菌RNase P RNA所必需的，但先前的研究对于其具体功能得出了相互矛盾的结论。在这里，我们使用生化和生物物理技术来研究该蛋白在大肠杆菌和枯草芽孢杆菌RNase P中所有提出的功能。我们证明，大肠杆菌蛋白而非枯草芽孢杆菌蛋白能稳定RNase P RNA的整体结构，尽管这两种蛋白都不同程度地影响全酶二聚体的形成和前体tRNA的识别。通过比较每种蛋白与其同源和非同源RNA形成的复合物，我们表明这两种全酶之间的差异主要存在于RNA而非每种全酶的蛋白质组分中。我们的结果调和了先前关于该蛋白作用的相互矛盾的结论，并支持一种模型，即该蛋白激活表现出多种全酶特性的局部RNA结构。
