Functional characterization of XendoU, the endoribonuclease involved in small nucleolar RNA biosynthesis
Functional characterization of XendoU, the endoribonuclease involved in small nucleolar RNA biosynthesis
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DOI：
10.1074/jbc.m501160200
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发表时间：
2005-05-13
影响因子：
4.8
通讯作者：
Caffarelli, E
中科院分区：
文献类型：
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作者：
Gioia, U;Laneve, P;Caffarelli, E
XendoU是参与非洲爪蟾内含子编码的小核仁RNA的特定亚类的生物合成的核糖核酸内切酶。XendoU与任何已知的细胞RNA酶都没有同源性，尽管它与暂时注释为丝氨酸蛋白酶的蛋白质具有序列相似性。最近已经表明，XendoU代表巢状病毒复制性核糖核酸内切酶（NendoU）的细胞对应物，其在病毒复制和转录中起关键作用。在本文中，我们结合预测和实验数据来定义直接参与XendoU催化的氨基酸残基。具体而言，我们发现XendoU残基Glu-161、Glu-167、His-162、His-178和Lys-224对于RNA切割是必需的，RNA切割在锰离子存在下发生。此外，我们确定了XendoU结合所需的RNA序列，并表明XendoU-RNA复合物的形成是Mn 2 +-独立的。
XendoU is the endoribonuclease involved in the biosynthesis of a specific subclass of Xenopus laevis intron-encoded small nucleolar RNAs. XendoU has no homology to any known cellular RNase, although it has sequence similarity with proteins tentatively annotated as serine proteases. It has been recently shown that XendoU represents the cellular counterpart of a nidovirus replicative endoribonuclease (NendoU), which plays a critical role in viral replication and transcription. In this paper, we combined prediction and experimental data to define the amino acid residues directly involved in XendoU catalysis. Specifically, we find that XendoU residues Glu-161, Glu-167, His-162, His-178, and Lys-224 are essential for RNA cleavage, which occurs in the presence of manganese ions. Furthermore, we identified the RNA sequence required for XendoU binding and showed that the formation of XendoU-RNA complex is Mn2+-independent.