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复合物的三维结构是了解其分子功能的先决条件。我们建议对几种与snRNP或SMN颗粒相关的DExD/H box蛋白以及布鲁氏T.编辑体的核酸酶进行晶体学研究。DExD/H box蛋白属于atp依赖性解旋酶家族，并表现出受dsRNA刺激的NTPase活性。实际上，只有少数DExD/H蛋白被证明可以解旋dsRNA，它们的活性和/或特异性可能依赖于其他蛋白。除了保守的解旋酶结构域外，许多DExD/H蛋白还含有额外的结构域，这些结构域对于与其他蛋白的相互作用很重要，可能会影响特异性和催化活性。一些DExD/H蛋白也可以破坏蛋白质-RNA复合物或影响RNA的折叠。前mrna的剪接至少需要8个DExD/H box蛋白。我们将重点分析snRNP相关的DExD/H盒蛋白U5-100K （Prp28p）、Prp22p和UAP56 （Sub2p）的晶体结构，它们都是mrna前剪接所必需的，以及DExD/H蛋白Gemin3 （Dp103）的晶体结构，它是参与snRNP生物发生的smn复合物的一部分。我们还将确定参与mRNA编辑的新型核酸酶TbMP42的晶体结构。所有这些晶体学研究将更好地解决功能蛋白质- rna或蛋白质-蛋白质复合物的结构。这些项目是与<s:1> hrmann， Fischer和Göringer小组合作进行的。

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.