Structural and functional analyses of archaeal sRNPs

描述(申请人提供)：核糖体RNA在生物发生过程中被共价修饰。未能正确修饰rRNA会影响蛋白质合成的效率，并可能参与肿瘤的形成和疾病的发病机制。真核生物和古生物中最普遍的rRNA修饰之一是核糖2‘-羟基的2’-O-甲基化。这些修饰是由保守的盒C/D小核仁RNA家族指导的，它包含终端盒C/D和并列的内盒CO/D没有图案。目前，古菌盒C‘/D’小核糖核蛋白(SRNPs)是目前唯一可以在体外重组获得具有酶活性的复合体的RNA引导的核苷酸修饰系统。这些系统的结构研究已经成熟，可以确定复杂组装的机制及其与调控的联系，并评估突变如何影响甲基化活性。 这项研究的长期目标是研究古生物中BOX C/D引导的2‘-O-甲基化系统的结构生物学，并将其与真核生物的相应系统进行比较。这项研究将专门研究简氏甲烷球菌和Pernix Aeropyrum box C/D rRNPs的结构和活性关系。在这些系统中，L7Ae核心蛋白通过结合box C/D RNA并与Nop56/58和纤维蛋白核心蛋白建立相互作用来启动sRNP组装。目的是阐明蛋白质-RNA和蛋白质/蛋白质的相互作用、结合、折叠和组装是如何调节生物活性的。 具体目标是： 1.将单个和并列的古生物盒C/D和C‘/D’SRNA基序与孤立和并列的L7Ae-box C/D和L7Ae-C‘/D’sRNP复合体的结构进行比较和对比； 2.研究古生菌核心蛋白L7Ae在启动sRNP组装中的作用以及锌在这些相互作用中的可能作用。 这项研究的基本原理是增加补充的生物物理和结构数据，以支持越来越多的关于古生物盒C/D RNA修饰系统的生化研究。这些研究将对核糖核蛋白酶复合体的进化和发展提供洞察，并阐明古生物和真核生物sRNP系统之间的异同。

DESCRIPTION (provided by applicant): Ribosomal RNAs are covalently modified during biogenesis. Failure to properly modify rRNA can affect the efficiency of protein synthesis and may be involved in tumor-formation and disease pathogenesis. One of the most prevalent rRNA modification in both eukaryotes and archaea is the 2'-O-methylation of ribose 2'-hydroxyl groups. These modifications are directed by the conserved family of box C/D small nucleolar RNAs, which contain terminal box C/D and juxtaposed internal box C
O/D
O motifs. At present, archaeal box C'/D' small ribonucleoproteins (sRNPs) are the only RNA-guided nucleotide modification systems that can be reconstituted in vitro to obtain enzymatically active complexes. These systems are ripe for structural investigations that determine the mechanism of complex-assembly and its linkage to regulation, and assess how mutations affect methylation activity. The long-term goals of this research are to investigate the structural biology of the box C/D-guided 2'-O-methylation systems in archaeal organisms and compare them to eukaryotic counterparts. This investigation will specifically examine the structure <--> activity relationship of the Methanocaldococcus jannaschii and Aeropyrum pernix box C/D sRNPs. In these systems, the L7Ae core protein initiates sRNP assembly by binding box C/D RNAs and establishing interactions with the Nop56/58 and fibrillarin core proteins. The goals are to elucidate how protein-RNA and protein/protein interactions, binding, folding, and assembly regulate biological activity. The specific aims are: 1. To compare and contrast the structures of the individual and juxtaposed archaeal box C/D and C'/D' sRNA motifs to those in isolated and juxtaposed L7Ae-box C/D and L7Ae-C'/D' sRNP complexes; and 2. To examine the archaeal core protein L7Ae's role in initiating sRNP assembly and the putative function of zinc in these interactions. The rationale for this investigation is to add complementary biophysical and structural data to support the mounting biochemical studies on archaeal box C/D RNA modification systems. These studies will provide insight to the evolution and development of ribonucleoprotein enzyme complexes, and illuminate the similarities and difference between the archaeal and eukaryotic sRNP systems.