NMR DETERMINATION OF STRUCTURE OF ALDH SIGNAL PEPTIDE

肝线粒体乙醛脱氢酶由核基因编码， 在核糖体上合成后，必须在两者之间运输 线粒体膜。已知这些基质空间线粒体 酶最初是作为较高分子量的前体合成的 带有N-端氨基酸延伸。在导入到 线粒体的延伸，称为信号肽或前导序列，是 被一种特定的酶去除。关于这三个人的实际情况，我们知之甚少 信号肽的空间结构。这项建议目的是利用 用二维核磁共振技术解决结构问题 与来自人、牛肉和牛的信号肽相对应的合成肽 大鼠杠杆乙醛脱氢酶。这将在溶液中完成，也将在 当多肽被结合到胶束上以模拟可能的 预计在多肽结合到膜上时会被发现。特定的 大鼠酶信号肽中的氨基酸将被改变 进行定点突变。与信号相对应的多肽 那些不是进口的突变体的多肽将被制造出来，他们的 结构已确定。我们的目标是理解结构在 进口过程。最近的研究表明，乙醇可以抑制 移位，因此结构也将在它存在的情况下确定 就像在螺旋稳定化合物存在的情况下。蛋白质的运输 进入细胞器是一项至关重要的细胞功能。了解该系统的结构 信号肽可能允许开发一种药物来抑制 进程。此外，如果发现酒精改变了构象， 肽它将表明酗酒的另一个后果 就是降低细胞运输蛋白质的能力。

Liver mitochondrial aldehyde dehydrogenase is coded by a nuclear gene and after being synthesized on a ribosome must be transported across the two mitochondrial membranes. It is known that these matrix space mitochondrial enzymes are initially synthesized as a higher molecular weight precursor with an N-terminal amino acid extension. After being imported into the mitochondria the extension, called a signal peptide or leader sequence, is removed by a specific protease. Little is known about the actual three dimensional structure of a signal peptide. The aim of this proposal is use 2-dimensional nuclear magnetic resonance to solve the structures of synthetic peptides corresponding to the signal peptide from human, beef and rat lever aldehyde dehydrogenase. This will be done in solution as well as when the peptide is bound to a micelle in order to simulate what could be expected to be found when the peptide is bound to a membrane. Specific amino acids in the rat enzyme's signal peptide will be changed by performing site directed mutagenesis. Peptides corresponding to the signal peptide of those mutants which are not imported will be made and their structure determined. The goal is to understand the role of structure in the import process. It has recently been shown that ethanol inhibits the translocation, hence structures will be determined in its presence as well as in the presence of helix-stabilizing compounds. Transport of proteins into organelles is a vital cell function. Knowing the structure of the signal peptide may allow for the development of a drug to inhibit the process. In addition, if alcohol is found to alter the conformation of the peptide it will indicate that an additional consequence of abusive drinking is to decrease the cell's ability to transport proteins.