PNPASE COMPLEX

该子项目是利用 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来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 在人类基因组中存在一种易于识别的PNPase-like分子，定位于线粒体，其缺陷导致线粒体功能障碍。重要的是，我们已经发现重组SUV 3和PNP之间在体外直接相互作用。我们计划进一步详细研究它们的相互作用，以测试SUV 3是否与PNTR在监测线粒体RNA降解方面协同工作。在降解体中是否存在与SUV 3/PNTR一起存在的其他蛋白质？如果是，它们在RNA降解中的作用是什么？从线粒体中分离和鉴定SUV 3/PNTR复合物是推进哺乳动物线粒体降解体研究的关键步骤。 Tao的实验室最近确定了甲型流感病毒NP的晶体结构。在晶体中组织为三聚体，NP折叠成具有与弹状病毒NP完全不同的拓扑结构的双结构域结构。 由残基402至428组成的短尾环可能在NP寡聚化中起重要作用，因为该区域中的单个残基突变导致寡聚化的完全丧失。在两个结构域之间的界面处的NP三聚体的外部鉴定出大的带正电荷的凹槽。外部RNA结合位点表明RNA可能暴露在流感病毒RNP中，这与非节段RNA病毒中的情况不同[2]。为了给我们的外部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复合物的结构。

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.