Manganese ions induce miscleavage in the Escherichia coli RNase P RNA-catalyzed reaction
Manganese ions induce miscleavage in the Escherichia coli RNase P RNA-catalyzed reaction
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DOI：
10.1006/jmbi.1999.3048
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发表时间：
1999-09-10
影响因子：
5.6
通讯作者：
Kirsebom, LA
中科院分区：
文献类型：
--
作者：
Brännvall, M;Kirsebom, LA
核糖核酸内切酶RNase P的切割需要二价金属离子的存在，其中Mg 2+促进最有效的切割。本文研究了Mg ~（2+）在RNase P RNA催化中的重要性。它表明，添加Mn 2+导致的裂解位点的移位，这种移位与动力学常数的变化，特别是k（猫）。我们的数据进一步表明，Mn ~（2+）对切割位点识别的影响取决于底物中的-1/+73碱基对和RNase P RNA-底物（RS）-复合物中的+73/294碱基对。基于我们的数据，我们建议，在Mg 2+作为唯一的二价金属离子的存在下，通过中间体进行切割，该中间体涉及在RS-复合物中建立+73/294碱基对。相比之下，添加Mn 2+有利于替代途径，其导致切割位点的移位。我们还研究了Mn ~（2+）对切割位点识别的影响以及使用在与底物的3'末端碱基配对的RNase P RNA区域中携带取代的各种RNase P RNA衍生物的切割动力学。从这些结果中，我们得出结论，这种RNase P RNA结构域的结构变化影响了二价金属离子参与切割的化学过程。(C)北京：科学出版社.
Cleavage by the endoribonuclease RNase P requires the presence of divalent metal ions, of which Mg2+ promotes most efficient cleavage. Here we have studied the importance of there being Mg2+ in RNase P RNA catalysis. It is demonstrated that addition of Mn2+ resulted in a shift of the cleavage site and that this shift was associated with a change in the kinetic constants, in particular k(cat). Our data further suggest that the influence of Mn2+ on cleavage site recognition depends on the -1/+73 base-pair in the substrate and the +73/294 base-pair in the RNase P RNA-substrate (RS)-complex. Based on our data we suggest that cleavage in the presence of Mg2+ as the only divalent metal ion proceeds through an intermediate which involves the establishment of the +73/294 base-pair in the RS-complex. By contrast, addition of Mn2+ favours an alternative pathway which results in a shift of the cleavage site. We also studied the influence of Mn2+ on cleavage site recognition and the kinetics of cleavage using various RNase P RNA derivatives carrying substitutions in the region of RNase P RNA that base-pair with the 3' terminal end of the substrate. From these results we conclude that a change in the structure of this RNase P RNA domain influences the involvement of a divalent metal ion(s) in the chemistry of cleavage. (C) 1999 Academic Press.