NMR DETERMINATION OF STRUCTURE OF ALDH SIGNAL PEPTIDE

肝线粒体醛脱氢酶由核基因编码， 在核糖体上合成后， 线粒体膜 据了解，这些基质空间线粒体 酶最初作为较高分子量的前体合成 N-末端氨基酸延伸。 在导入到 线粒体的延伸，称为信号肽或前导序列， 被一种特殊的蛋白酶去除 关于实际的三个人知之甚少 信号肽的三维结构。 该提案的目的是使用 2-三维核磁共振，以解决的结构， 对应于来自人、牛肉和牛的信号肽的合成肽， 大鼠肝醛脱氢酶 这将在溶液中完成， 当肽与胶束结合时， 预期当肽与膜结合时发现。 具体 大鼠酶的信号肽中的氨基酸将被改变， 进行定点诱变。 对应于信号的肽 将制备未输入的那些突变体的肽，并且它们的 结构确定。 我们的目标是了解结构在 进口过程。 最近的研究表明，乙醇可以抑制 易位，因此结构也将在其存在下确定 如在螺旋稳定化合物的存在下。 蛋白质转运 是细胞的重要功能 了解了 信号肽可以允许开发药物来抑制 过程 此外，如果发现酒精改变了 它将表明，滥用饮酒的另一个后果是， 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.