PNPASE COMPLEX

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在人类基因组中存在一种易于识别的PNPase样分子，它定位于线粒体，其缺失导致线粒体功能障碍。重要的是，我们在体外发现了重组SUV3与PNPase之间的直接相互作用。我们计划进一步详细研究它们的相互作用，以测试SUV3是否与PNPase在监控线粒体RNA降解方面协同工作。除SUV3/PNPase外，降解体中还存在其他蛋白质吗？如果是，它们在RNA降解中起什么作用？从线粒体中分离和鉴定SUV3/PNPase复合体是推进哺乳动物线粒体降解体研究的关键步骤。 最近，陶的实验室确定了甲型流感病毒NP的晶体结构。NP在晶体中以三聚体的形式折叠成两个结构域，具有与横纹病毒NP完全不同的拓扑结构。由402至428残基组成的短尾环可能在NP寡聚中发挥重要作用，因为该区域的单个残基突变导致寡聚完全丧失。在两个结构域之间的界面上，在NP三聚体的外部发现了一个大的带正电的凹槽。外部RNA结合位点表明，与非节段RNA病毒不同，流感病毒RNPs中的RNA很可能暴露在RNA中。为了为我们的外部RNA结合模型提供明确的证据，并阐明RNP的结构和组装，我们建议确定NP：RNA复合体的结构。

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. There is a readily recognizable PNPase-like molecule in human genome, which localizes to mitochondria and its deficiency leads to mitochondrial dysfunction. Importantly, we have found that a direct interaction between recombinant SUV3 and PNPase in vitro. We plan to further examine their interaction in detail to test whether SUV3 works in concert with PNPase in monitoring mitochondrial RNA degradation. Are there other proteins in degradosome together with SUV3/PNPase? If yes, what are their roles in RNA degradation? To isolate and identify the SUV3/PNPase complex from mitochondria are critical steps in advancing the current knowledge on mammalian mitochondrial degradosome. The crystal structure of influenza A virus NP has recently been determined in Tao's laboratory. Organized as trimers in the crystal, NP folds into a two-domain structure with a topology completely different from that of the rhabdovirus NP. A short tail loop, consisting of residues 402 to 428, is likely to play an important role in NP oligomerization, as single-residue mutation in this region causes a total loss of oligomerization. A large positively charged groove was identified at the exterior of the NP trimer at the interface between the two domains. An external RNA binding site indicates that RNA is likely to be exposed in the influenza virus RNPs, different from the situation in non-segmented RNA viruses [2]. To provide a definite evidence for our external RNA binding model and to elucidate RNP structure and assembly, we propose to determine the structure of the NP:RNA complex.