Structure of Escherichia coli RNase E catalytic domain and implications for RNA turnover
Structure of Escherichia coli RNase E catalytic domain and implications for RNA turnover
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DOI：
10.1038/nature04084
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发表时间：
2005-10-20
期刊：
影响因子：
64.8
通讯作者：
Luisi, BF
中科院分区：
文献类型：
--
作者：
Callaghan, AJ;Marcaida, MJ;Luisi, BF
基因表达的协调调节是所有生物体内平衡、生长和发育所必需的。这种协调可能在信使RNA稳定性水平上部分实现(1)，其中对转录物亚群的靶向破坏产生了交叉调节代谢途径的潜力。在大肠杆菌中，转录物群体的平衡和组成受到RNase E的影响，RNase E是一种重要的核糖核酸内切酶，不仅可以转化RNA，还可以加工某些关键的RNA前体（2-10）。RNase E在内部切割RNA，但其催化能力取决于底物的50端，即使它位于距离切割位点较远的位置（11-14）。在这里，我们报道了RNase E的催化结构域的晶体结构作为与RNA底物捕获的变构中间体。RNase E催化结构域的四个亚基结合成一个交织的四级结构，解释了为什么亚基组织是催化活性所必需的。包含活性位点的亚结构域在结构上与脱氧核糖核酸酶一致，在RNA和DNA核酸酶的进化史上建立了意想不到的联系。这种结构解释了对底物50末端的识别如何触发催化作用，也揭示了RNase E如何选择性地处理而不是破坏特定RNA前体的问题。
The coordinated regulation of gene expression is required for homeostasis, growth and development in all organisms. Such coordination may be partly achieved at the level of messenger RNA stability(1), in which the targeted destruction of subsets of transcripts generates the potential for cross-regulating metabolic pathways. In Escherichia coli, the balance and composition of the transcript population is affected by RNase E, an essential endoribonuclease that not only turns over RNA but also processes certain key RNA precursors(2-10). RNase E cleaves RNA internally, but its catalytic power is determined by the 50 terminus of the substrate, even if this lies at a distance from the cutting site(11-14). Here we report crystal structures of the catalytic domain of RNase E as trapped allosteric intermediates with RNA substrates. Four subunits of RNase E catalytic domain associate into an interwoven quaternary structure, explaining why the subunit organization is required for catalytic activity. The subdomain encompassing the active site is structurally congruent to a deoxyribonuclease, making an unexpected link in the evolutionary history of RNA and DNA nucleases. The structure explains how the recognition of the 50 terminus of the substrate may trigger catalysis and also sheds light on the question of how RNase E might selectively process, rather than destroy, specific RNA precursors.