Fungal mitochondrial porins and DNA polymerases

线粒体是膜结合的细胞器，是真核细胞中能量产生的关键。线粒体的功能取决于代谢物在两个线粒体膜上的交换。我们的研究调查了孔蛋白的结构，孔蛋白是一种允许水溶性小分子穿过外膜的蛋白质。这种分子也可能参与调节程序性细胞死亡，这是正常发育和包括癌症在内的疾病状态的重要参与者。因此，了解孔蛋白的结构是至关重要的，以确定蛋白质如何执行这些功能，以及它如何与细胞的其余部分相互作用。为此，我们正在使用重组孔蛋白从脉孢菌，这是在大肠杆菌中过表达。不同的洗涤剂系统正在评估的手段折叠孔蛋白在膜的情况下，允许结构测定的方法，如核磁共振光谱（NMR）。此外，我们正在研究在蛋白质合成后将其引导到线粒体的信号，并确定与膜两侧的其他蛋白质相互作用的蛋白质区域，从而可能有助于调节其功能。 我们研究的第二部分涉及线粒体DNA复制。线粒体含有对所有专性需氧生物体都必不可少的小基因组。在真菌中，复制这种DNA的酶，即线粒体DNA聚合酶，包含一个功能未知的结构域。拟议的研究将调查该结构域在酵母蛋白中的功能，最终目标是了解DNA聚合酶可以进行有效的进行性合成的不同方式。总之，这些项目有助于围绕这些基本细胞器的维护及其与细胞其他部分的相互作用的知识体系。

Mitochondria are membrane-bound organelles that are key to energy production in eukaryotic cells. The function of mitochondria depends on the exchange of metabolites across the two mitochondrial membranes. Our research investigates the structure of porin, a protein that allows the passage of small, water soluble molecules across the outer membrane. This molecule may also be involved in the regulation of programmed cell death, an important player in normal development, and in disease states including cancer. Therefore, an understanding of porin structure is essential in order to determine how the protein carries out these functions, and how it interacts with the rest of the cell. To this end, we are using recombinant porin from Neurospora, that is overexpressed in Escherichia coli. Different detergent systems are being evaluated as the means to fold porin in the absence of membranes, to allow structural determination by methods like nuclear magnetic resonance spectroscopy (NMR). In addition, we are investigating the signals that direct the protein to mitochondria following its synthesis, and determining the regions of the protein that interact with other proteins on both sides of the membrane, and thereby may contribute to the regulation of its function.      The second part of our research deals with mitochondrial DNA replication. Mitochondria contain small genomes that are essential to all obligately aerobic organisms. In fungi, the enzyme that replicates this DNA, the mitochondrial DNA polymerase, contains a domain of unknown function. The proposed research will investigate the function of this domain in the yeast protein, with the ultimate goal of understanding the different ways in which DNA polymerases can carry out effective, processive synthesis. Together, these projects contribute to the body of knowledge surrounding the maintenance of these essential organelles, and their interactions with the rest of the cell.