Molecular Basis for the Recognition and Cleavage of RNA by the Bifunctional 5′-3′ Exo/Endoribonuclease RNase J
Molecular Basis for the Recognition and Cleavage of RNA by the Bifunctional 5′-3′ Exo/Endoribonuclease RNase J
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DOI：
10.1016/j.str.2011.06.018
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发表时间：
2011-09-07
期刊：
影响因子：
5.7
通讯作者：
Condon, Ciaran
中科院分区：
文献类型：
--
作者：
Dorleans, Audrey;de la Sierra-Gallay, Ines Li;Condon, Ciaran
RNase J是原核生物中参与RNA成熟和周转的金属-β-内酰胺酶的β-CASP家族的关键成员。B。枯草杆菌酶具有5 '-3'核糖核酸外切和内切活性，这是核糖核酸酶的一种不寻常的性质。在这里，我们介绍了T的晶体结构。嗜热菌RNA酶J结合4个核苷酸的RNA。该结构揭示了RNA结合通道，说明了酶如何以5 '-3'核糖核酸外切模式发挥作用以及它如何作为内切核酸酶发挥作用。第二个带负电荷的隧道从活性位点引出，并且理想地定位成以5 '-3'核酸外切酶模式排空切割的核苷酸。我们证明了B。枯草杆菌RNA酶J1对长RNA表现出加工行为，对长度小于5个核苷酸的底物表现出分布性。我们提出了一个模型，涉及结合的RNA表面的β-CASP结构域来解释酶的进行性行动。
RNase J is a key member of the beta-CASP family of metallo-beta-lactamases involved in the maturation and turnover of RNAs in prokaryotes. The B. subtilis enzyme possesses both 5'-3' exoribonucleolytic and endonucleolytic activity, an unusual property for a ribonuclease. Here, we present the crystal structure of T. thermophilus RNase J bound to a 4 nucleotide RNA. The structure reveals an RNA-binding channel that illustrates how the enzyme functions in 5'-3' exoribonucleolytic mode and how it can function as an endonuclease. A second, negatively charged tunnel leads from the active site, and is ideally located to evacuate the cleaved nucleotide in 5'-3' exonucleolytic mode. We show that B. subtilis RNase J1, which shows processive behavior on long RNAs, behaves distributively for substrates less than 5 nucleotides in length. We propose a model involving the binding of the RNA to the surface of the beta-CASP domain to explain the enzyme's processive action.