CRYSTAL STRUCTURE OF THE COMPLEX OF PKR AND HIV TAR RNA

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们的工作分为三个部分：a) PKR和HIV TAR RNA复合物的晶体学研究。b) HIV TAR结构的高分辨率晶体学研究c) IKK激酶复合物的晶体学研究。人类dsRNA活化蛋白激酶（PKR）是干扰素诱导基因的产物，是人类先天防御系统的关键组成部分。在对病毒感染的反应中，PKR通过磷酸化其丝氨酸51残基来抑制翻译因子eIF-2a。PKR通过调节一些重要的转录因子参与转录。PKR激活的关键步骤是dsRNA以序列独立的方式相互作用。结合后，PKR经历构象重排和自磷酸化。本研究的长期目标是了解dsRNA:PKR相互作用和蛋白激酶激活的分子性质。为了深入了解dsRNA:PKR相互作用的分子性质，我们在C2空间组中对PKR和TAR 57 RNA的复合物进行了结晶，细胞参数分别为80.42、45.99、254.42¿和a=90？00, b = 97 ?。25和g=90？初步结果表明，在单位细胞中存在4个PKR分子，并且可能由2个PKR分子和1个TAR¿1 57 RNA组成。所得结果与中子散射的研究结果一致。

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 work is in three parts: a) Crystallographic study of complex of PKR and HIV TAR RNA. b) Crystallographic study of HIV TAR structure at high resolution c) Crystallographic study of IKK kinase complex. The human dsRNA activated protein kinase (PKR) is a product of an interferon-induced gene and a key component of the human innate defense system. In response to viral infection, PKR inhibits translation factor eIF-2a via phosphorylation of its serine 51 residue. PKR is involved in transcription by regulating some important transcription factors. A critical step in the activation of PKR is the interaction of dsRNA in a sequence¿independent manner. Upon binding, PKR undergoes conformational rearrangement and autophosphorylation. The long-term objective of this study is to understand the molecular nature of the dsRNA:PKR interaction and protein kinase activation. HIV-1 TAR dsRNA activates PKR both in vivo and in vitro, exhibiting a concentration-dependent, activation-inhibition curve typical of dsRNA To obtain insight into the molecular nature of dsRNA:PKR interaction, the complex of PKR and TAR 57 RNA was crystallized in a C2 space group with cell parameters: 80.42, 45.99, 254.42 ¿ and a=90?00, b=97?.25 and g=90?.00. The preliminary results indicate the presence of four PKR molecules in the unit cell and the possibility of a composition of two PKR molecules and one TAR ¿1 57 RNA. The results are consistent with those of the Neutron Scattering studies.