ENYZMES AFFECTING THE ACCUMULATION OF ALTERED PROTEINS

描述：(改编自应用程序)。衰老的表现 部分原因是随着时间的推移，细胞的自我修复效率变低。 这些反应代表了生物体为维持 基本大分子在分子表面的结构完整性 内在的不稳定性。这些机制中的缺陷可能是病理的基础。 在那里可以加速老化过程。这项工作的目标是 了解老化的生物体如何防止共价变化的积累 可以损害细胞功能的蛋白质。这些调查人员将 L-异门冬氨酸(D-天冬氨酸)蛋白的功能表征 O-甲基转移酶识别自发损伤的蛋白质和 催化蛋白质修复反应的初始步骤。发现了 这一途径揭示了大分子修复可能不仅仅是DNA的修复，而是 对于蛋白质也是如此。这些调查人员提议问一问，潜在的 衰老过程中受损蛋白质的积累通过甲基化和其他方式减少 在万岁中的路径。他们将利用包括细菌在内的模型生物， 酵母、蠕虫和植物。具体地说，我们将描述蛋白质损伤的特征 在大肠杆菌中。他们将研究突变的表型 甲基转移酶pcm基因和Sure基因都存在于 一台装有pcm的操纵台。他们还将研究相关酶的作用，这些酶 参与了含有异天冬氨酸的蛋白质的新陈代谢 多肽，包括异天冬氨酸二肽酶。他们将分析变种人 木瓜线虫体内的蛋白质修复甲基转移酶 很优雅。他们会问，酿酒酵母如何避免 含有改变的天冬氨酸残基的蛋白质的积累 事实上，它天生就缺乏甲基转移酶。最后，他们会 研究甲基化反应在控制蛋白质损伤中的作用 高等植物，包括玉米和拟南芥。这些研究有望 不仅为观察蛋白质生命提供了一个新的窗口，而且可能还表明 生物衰老过程可能与细胞能保持多好的状态密切相关 无自发共价损伤的多肽。

DESCRIPTION: (Adapted from the Application). The manifestations of aging result in part from cells becoming less efficient at self-repair with time. These reactions represent one part of the battle of organisms to maintain the structural integrity of essential macromolecules in the face of the molecules intrinsic instabilities. Defects in these mechanisms may underlie pathologies where the aging process can be accelerated. The objective of this work is to understand how aging organisms prevent the accumulation of covalently altered proteins that can compromise cellular functions. These investigators will characterize the role of the protein L-isoaspartate (D-aspartate) O-methyltransferase that recognizes spontaneously-damaged proteins and catalyzes the initial step of a protein repair reaction. The discovery of this pathway reveals that macromolecular repair may not be just for DNA, but for proteins as well. These investigators propose to ask how the potential accumulation of damaged proteins in aging is reduced by methylation and other pathways in viva. They will utilize model organisms including bacteria, yeast, worms, and plants. Specifically, we will characterize protein damage in the bacterium Escherichia coli. They will study mutant phenotypes of both the methyltransferase pcm gene and the sure gene shown to be present in an operon with pcm. They will also study the role of associated enzymes that are involved in the metabolism of isoaspartyl-containing proteins and peptides, including isoaspartyl dipeptidases. They will analyze mutants of the protein repair methyltransferase in the nematode worm Casnorhabditis elegant. They will ask how the yeast Saccharomyces cerevisiae can avoid the accumulation of proteins containing altered aspartyl residues in spite of the fact that it naturally lacks the methyltransferase. Finally, they will examine the role of the methylation reaction in controlling protein damage in higher plants, including corn and Arabidopsis. These studies will hopefully not only provide a new window to view protein life but may also suggest that the biological aging process may be closely linked to how well cells can keep polypeptides free of spontaneous covalent damage.