PROTEIN CONFORMATION

蛋白质中结构修饰的出现是生物衰老的一个有充分证据的症状，可以用来研究后一种过程。这个项目的主要目标是收集600只UM-HET3小鼠的蛋白质状态的年龄敏感指标的数据，以提供影响蛋白质功能的基因座上MAP位置的信息，并测试蛋白质状态与衰老速度的其他结构和功能指标之间的暗示相关性。该项目专注于两种蛋白质，糖酵解酶磷酸甘油酸激酶(PGK)和眼晶状体蛋白质，特别是伴侣蛋白α-晶体蛋白。这两个蛋白质系统具有非常不同的结构、生物学和物理特性，但它们都会随着小鼠的衰老而改变。项目4的具体目标包括：91)检测种群1的600只小鼠的脑、心脏和肝脏中PGK的热失活率和免疫滴定数据。6-27个月大鼠的热失活率下降了7倍，而免疫异常的PGK在大多数组织中出现了不同年龄的异常。(2)通过对分子量、结构和光谱特征的变化敏感的光学技术，对这600只小鼠的眼晶状体蛋白质的修饰程度进行量化，以应用于完整的晶状体和提取的晶状体蛋白质。(3)同样的测试将在种群2中遗传选择(和对照)的小鼠身上进行，以寻找改变寿命的等位基因也影响蛋白质构象和交联性。除了提供可能控制这些年龄敏感特征的基因的信息外，我们的数据还应该有助于确定动物之间蛋白质状态的差异是否可能导致年龄敏感组织(骨骼、肌肉、免疫系统)的功能变化，以及蛋白质功能状态是否可能受到项目5中提到的氧化和糖氧化过程的调节。这些比较只能在多学科项目的背景下进行，将检验我们的假设，即与年龄相关的生化特征将与其他年龄敏感表型相关，并处于重叠的遗传控制之下。除了以上列出的与整个项目相关的目标外，项目4还将解决以下项目具体问题：1.测试旧眼晶状体中蛋白质聚集倾向的增加是否由于α-晶体蛋白提供的保护减少所致。2.寻找与年龄相关的α-晶体蛋白作为伴侣蛋白功能丧失的分子根源。3.开发和测试额外的蛋白质修饰实验方法--研究，将在未来的计划工作中应用。

The appearance of structural modifications in proteins is a well documented symptom of biological aging which can be used to study the latter process. The major goal of this project is to collect data on age-sensitive measures of protein status in a cohort of 600 UM-HET3 mice to provide information about map positions on loci that influence protein function, and to test for suggestive correlations between protein status and other structural and functional indices of aging rate. The project focuses on two proteins, the glycolytic enzyme phosphoglycerate kinase (PGK) and the eye lens proteins, in particular the chaperone-protein alpha-crystallin. These two protein systems have very different structures, biological and physical characteristics, but both are altered by aging in mice. The specific aims of Project 4 include: 91) To examine thermal inactivation rate and immunotitration data for PGK in brain, heart and liver in the 600 mice of Population 1. Thermal inactivation rate decline sup to 7-fold between 6 and 27 months in rats, while immunologically abnormal PGK appear to various ages in most tissues. (2) To quantitate the extent of modification of eye lens proteins in these 600 mice by optical techniques with sensitivity to changes in molecular weight, in structure and in spectroscopic signatures, to be applied both to intact lenses and to extracted lens proteins. (3) The same battery of tests will be performed ont he genetically selected (and control) mice in Population 2 to see in alleles that alter longevity also influence protein conformation and cross-linking. In addition to providing information about genes that may control these age-sensitive traits, our data should help to determine whether inter-animal differences in protein status might contribute to functional changes in age-sensitize tissues (bone, muscle, immune system) and whether protein functional status is likely to be regulated by oxidation and glycoxidation processes addressed in Project 5. The comparisons, which can only be made in the context of a multi- disciplinary program project, will test our hypothesis that biochemical signatures that correlate with older age will be associated with other age-sensitize phenotypes and be under over-lapping genetic control. In addition to the above listed aims, which pertain to the Program as a whole, Project 4 will also address the following project-specific issues: 1. Test whether the increased aggregation-propensity of proteins in the old eye lens is due to a reduction in the protection afforded by alpha-crystallin. 2. Search for the molecular origin of the age-related loss in alpha-crystallin's efficacy as a chaperone protein. 3. Develop and test additional experimental approaches for protein-modifications- studies, to be applied in future Program work.