Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
RNA. 2010 Mar;16(3):553-62. doi: 10.1261/rna.1858010. Epub 2010 Jan 27.
The Escherichia coli endoribonuclease RNase E is an essential enzyme having key roles in mRNA turnover and the processing of several structured RNA precursors, and it provides the scaffold to assemble the multienzyme RNA degradosome. The activity of RNase E is inhibited by the protein RraA, which can interact with the ribonuclease's degradosome-scaffolding domain. Here, we report that RraA can bind to the RNA helicase component of the degradosome (RhlB) and the two RNA-binding sites in the degradosome-scaffolding domain of RNase E. In the presence of ATP, the helicase can facilitate the exchange of RraA for RNA stably bound to the degradosome. Our data suggest that RraA can affect multiple components of the RNA degradosome in a dynamic, energy-dependent equilibrium. The multidentate interactions of RraA impede the RNA-binding and ribonuclease activities of the degradosome and may result in complex modulation and rerouting of degradosome activity.
大肠杆菌内切核糖核酸酶 RNase E 是一种必需的酶，在 mRNA 周转和几种结构 RNA 前体的加工中具有关键作用，它为组装多酶 RNA 降解体提供了支架。RNase E 的活性受到蛋白质 RraA 的抑制，RraA 可以与核糖核酸酶的降解体支架结构域相互作用。在这里，我们报告 RraA 可以与降解体的 RNA 解旋酶成分（RhlB）以及 RNase E 的降解体支架结构域中的两个 RNA 结合位点结合。在 ATP 的存在下，解旋酶可以促进 RraA 与稳定结合在降解体上的 RNA 交换。我们的数据表明，RraA 可以在动态、能量依赖的平衡中影响 RNA 降解体的多个成分。RraA 的多齿相互作用阻碍了降解体的 RNA 结合和核糖核酸酶活性，可能导致降解体活性的复杂调节和改道。
