RNA RECOGNITION BY LA AUTOANTIGEN

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 我们的研究工作集中在人La NTD蛋白-RNA复合物的结构上，以确定La自身抗原靶向新生RNA转录物3-末端的结合亲和力和特异性的分子基础。 我们已经使用NMR光谱质量来筛选一系列的RNA寡聚体终止与UUUOH 3-末端的能力，形成复合物与La NTD在溶液中。最好的NMR光谱被发现为配合物的La NTD与UUUOH 3-mer和9-mer RNA寡聚体含有3-UUUOH结束，与后者产生衍射质量的晶体。晶体属于空间群P21212，每个不对称单元具有两个复合分子，并且在家庭X射线源处衍射至2.9 A。用分子置换法，在APS的19 ID光束线上，从天然晶体中收集了X射线数据，找到了部分结构解。我们已经结晶复合物硒蛋氨酸（SeMet）蛋白质，以获得实验阶段的结构测定。我们的长期目标是研究单个NTD和CTD以及全长La蛋白识别RNA的基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our research efforts are focused on the structure of human La NTD protein-RNA complex to define the molecular basis for binding affinity and specificity of La autoantigen targeted to the 3-end of nascent RNA transcripts. We have used NMR spectral quality to screen a series of RNA oligomers terminating with UUUOH 3-ends for their ability to form complexes with La NTD in solution. The best NMR spectra were found for complexes of La NTD with the UUUOH 3-mer and 9-mer RNA oligomers containing 3-UUUOH ends, with the later yielding diffraction quality crystals. The crystals belong to space group P21212 with two complex molecules per asymmetric unit and diffracted to 2.9 A at home X-ray source. Partial structure solution has been found by molecular replacement method using x-ray data collected from native crystal at 19ID beamline at APS. We have crystallized complex with selenomethionine (SeMet) protein to obtain experimental phases for structure determination. Our long-term goal is to investigate basis of RNA recognition by the individual NTD and CTD as well as full-length La protein.