Brännvall M, Mattsson J G, Svärd S G, Kirsebom L A
Biomedical Centre, Uppsala, SE-751 23, Sweden.
J Mol Biol. 1998 Nov 6;283(4):771-83. doi: 10.1006/jmbi.1998.2135.
The function of RNase P RNA depends on its folding in space. A majority of RNase P RNAs from various bacteria show a similar secondary structure to that of Escherichia coli (M1 RNA). However, there are exceptions as exemplified by the RNase P RNA derived from the low GC-content Gram-positive bacteria Bacillus subtilis and Mycoplasma hyopneumoniae (Hyo P RNA). Previous studies using M1 RNA and Hyo P RNA suggest differences both with respect to the kinetics of cleavage as well as to cleavage site recognition. Here we have studied cleavage by these two structurally different RNase P RNAs as a function of changes in the 5' leader and the 3'-terminal CCA motif in the substrate. Our data suggest that the nucleotide at the -2 position in the 5' leader plays a role both for cleavage site recognition and for the rate of cleavage. However, depending on the identity of the -2 residue differences in the cleavage pattern comparing these two types of RNase P RNAs were observed. The results also suggest that the identity of the -1/+73 base-pair in the substrate influences the cleavage site recognition process. These findings will be related to differences in structure comparing these types of RNase P RNAs and the "RCCA-RNase P RNA" interaction. In addition, our findings will be discussed with respect to the primary structure of the tRNA genes in different bacteria.
核糖核酸酶P RNA的功能取决于其在空间中的折叠。来自各种细菌的大多数核糖核酸酶P RNA显示出与大肠杆菌（M1 RNA）相似的二级结构。然而，也有例外，如来自低GC含量革兰氏阳性菌枯草芽孢杆菌和猪肺炎支原体的核糖核酸酶P RNA（Hyo P RNA）。先前使用M1 RNA和Hyo P RNA的研究表明，在切割动力学以及切割位点识别方面都存在差异。在这里，我们研究了这两种结构不同的核糖核酸酶P RNA的切割作用，它是底物中5'前导序列和3'-末端CCA基序变化的函数。我们的数据表明，5'前导序列中-2位置的核苷酸在切割位点识别和切割速率方面都起作用。然而，根据-2残基的身份，观察到比较这两种类型的核糖核酸酶P RNA时切割模式存在差异。结果还表明，底物中-1/+73碱基对的身份会影响切割位点识别过程。这些发现将与比较这些类型的核糖核酸酶P RNA的结构差异以及“RCCA-核糖核酸酶P RNA”相互作用相关。此外，我们将针对不同细菌中tRNA基因的一级结构来讨论我们的发现。
