STRUCTURE OF NATURALLY FOLDED APOPTOSIS INDUCING FACTOR

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。 含有FAD的哺乳动物细胞凋亡诱导因子(AIF)是一种古老的caspase非依赖性死亡效应因子，通常存在于线粒体膜间间隙，但在诱导凋亡时转移到细胞核，并引发染色质凝聚和大规模DNA片段化。尽管有强有力的证据表明AIF与自由基动态平衡和氧化应激有关，但该蛋白诱导细胞凋亡的生理功能和机制尚不清楚。到目前为止，只有截断的、重折叠的致凋亡性AIF的晶体结构是可用的。我们发现复性和截断显著干扰了黄素蛋白的氧化还原特性。因此，获得自然折叠、健康？的结构信息。AIF的形式对于了解线粒体中蛋白质的结构/功能关系和生理作用是至关重要的。我们得到了AIF自然折叠的催化结构域(残基77-612)的良好衍射晶体，但由于晶胞尺寸较大，目前X射线模型的分辨率限制在3.2？，这是探测器尺寸的限制。我们的目标是通过收集2-theta角设置为10-20？的同步加速器数据来扩展分辨率。

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. A FAD-containing mammalian apoptosis inducing factor (AIF) is a phylogenetically old caspase-independent death effector that normally resides in the mitochondrial intermembrane space but upon apoptosis induction translocates to the nucleus and triggers chromatin condensation and large scale DNA fragmentation. Although there is strong evidence that AIF is linked to free radical homeostasis and oxidative stress, neither physiological function nor mechanism of apoptosis induced by this protein is known. To date, only the crystal structures of truncated, refolded forms of apoptogenic AIF are available. We found that refolding and truncation significantly perturb the redox properties of the flavoprotein. Thus, obtaining structural information on naturally folded, ?healthy? form of AIF is vital for understanding structure/function relationships and the physiological role of the protein in mitochondria. We obtained well-diffracting crystals of the naturally folded catalytic domain of AIF (residues 77-612) but owing to large cell dimensions the current resolution of the x-ray model is limited to 3.2 ¿, the detector size limit. We aim to extend the resolution by collecting the synchrotron data with the 2-theta angle set to 10-20¿.