Crystallographic studies on snRNP-and SMN-Associated DExD/H-box proteins and on the editosome-specific nuclease TbMP42

确定参与mRNA成熟的蛋白质-RNA复合体的三维结构是了解其分子功能的前提。我们提出了几种与SnRNP或SMN颗粒相关的DExD/H盒蛋白的结晶学研究，以及布鲁氏锥虫编辑体核酸酶的研究。DExD/H box蛋白属于ATP依赖的解旋酶家族，具有受dsRNA刺激的NTPase活性。事实上，只有少数DExD/H蛋白被证明可以解开dsRNA，它们的活性和/或特异性可能依赖于其他蛋白质。除了保守的解旋酶结构域，许多DExD/H蛋白还含有额外的结构域，这些结构域对与其他蛋白质的相互作用非常重要，并可能影响其特异性和催化活性。一些DExD/H蛋白还可以破坏蛋白质-RNA复合体或影响RNA的折叠。至少需要8个DExD/H盒蛋白来剪接前-mRNAs。我们将集中讨论与SnRNP相关的DexD/H盒蛋白U5-100K(Prp28p)、Prp22p和UAP56(Sub2p)以及参与SnRNP生物发生的SMN复合体中的DexD/H蛋白Gmin3(DP103)的晶体结构分析。我们还将确定参与mRNA编辑的新型核酸酶TbMP42的晶体结构。所有这些结晶学研究都将优先解决蛋白质-RNA或蛋白质-蛋白质复合体的结构。这些项目是与Lührmann、费希尔和Göringer团队合作进行的。

The determination of the three-dimensional structures of protein-RNA complexes involved in mRNA maturation is a prerequiste for an understanding of their molecular function. We propose crystallographic studies on several DExD/H box proteins associated with snRNP or SMN particles as well as on a nuclease of the editosome from T. brucei. The DExD/H box proteins belong to the family of ATP-dependent helicases and exhibit an NTPase activity stimulated by dsRNA. Only a few DExD/H proteins have actually been show n to unwind dsRNA, and their activity and/or specificity might dependent on other proteins. Besides the conserved helicase domain, many DExD/H proteins contain additional domains, which are important for the interaction with other proteins and might affect the specificity and catalytic activity. Some DExD/H proteins can also disrupt protein-RNA complexes or affect the folding of RNA. At least eight DExD/H box proteins are required for the splicing of pre-mRNAs. We will focus on the crystal structure analysi s of the snRNP-associated DExD/H box proteins U5-100K (Prp28p), Prp22p and UAP56 (Sub2p), all required for pre-mRNA splicing, and of the DExD/H protein Gemin3 (Dp103), which is part of the SMN-complex involved in snRNP biogenesis. We will also determine the crystal structure of the novel nuclease TbMP42, which is involved in mRNA editing. All these crystallographic studies will preferably address the structures of functional protein-RNA or protein-protein complexes. The projects are carried out in collabora tion with the groups of Lührmann, Fischer and Göringer.