Investigation of transglutaminase-induced structural change of proteins related to degenerative diseases

多种蛋白质种类参与人类退行性疾病如阿尔茨海默病和朊病毒疾病的发病机制。这些蛋白质分子是病理相关的生化修饰的靶标，包括转氨酶催化的修饰（TG修饰），其在患者体内诱导相当复杂的分子过程。在研究期间，我们的研究主要集中在与淀粉样蛋白相关的事件。我们已经研究了生化作用对淀粉样蛋白形成的分子机制，如TG修饰和磷酸化。为了进行详细的研究，合成了来自致病蛋白的淀粉样短肽，并通过多种光谱和显微镜方法分析了它们的分子结构和聚集特性。实验研究结果包括：1.多聚谷氨酰胺肽和tau衍生的核心肽的淀粉样蛋白形成是 关于我们 被TG修饰强烈抑制。几种不同的分子机制，如直接在肽序列上引入负电荷或与多胺交联，可能引起抑制作用. tau衍生肽的淀粉样蛋白形成也非常有效地受到磷酸化的影响，主要是通过引入磷酸基团的负电荷及其与相邻带电残基的相互作用。该效应强烈依赖于磷酸化位点的位置。我们还发现，微量的磷酸化分子可以改变整个系统的聚集倾向，在上述研究中，我们还发现，生化修饰的效果强烈依赖于环境因素。为了更深入地了解环境对生化修饰淀粉样蛋白形成的影响，我们研究了非线性复杂的环境对淀粉样蛋白形成的影响。此外，为了将来扩展本分析，我们还使用化学修饰的膜蛋白进行了一些方法学研究。少

A variety of protein species are involved in pathogenesis of human degenerative diseases such as Alzheimer's and prion diseases. These protein molecules are targets of pathologically relevant biochemical modifications including transglutaminase-catalyzed modification (TG modification), which induce quite complex molecular processes in the patients' bodies. During the research period, our study mainly focused the events related to amyloidgenic proteins. We have investigated molecular mechanisms of biochemical effects upon the amyloid formation such as those by TG modification and phosphorylation. For detailed studies, amyloidgenic short peptides derived from pathogenic proteins were synthesized with or without the biochemical modifications, and their molecular structures and aggregation properties were analyzed by many spectroscopic and microscopic methods. The results of our experimental studies include:1. Amyloid formations of polyglutamine peptides and tau-derived core peptides were … More strongly inhibited by the TG modification. Several different molecular mechanisms, such as direct introduction of negative charges on the peptide sequence or cross-linking with polyamines, plausibly caused the inhibition effects.2. Amyloid formation of the tau-derived peptides was also influenced by phosphorylation very efficiently, mainly by introduction of negative charges of the phosphate group and their interactions with the neighboring charged residues. The effects depended strongly upon the position of the phosphorylation site. We have also found that a trace amount of phosphorylated molecules can alter the aggregation propensity of the whole system.During the studies above, we also found that the effects of the biochemical modifications depended strongly upon environmental factors. For getting deeper insights into environmental effects upon the biochemically modified amyloid formation, we investigated non-linearly complex environmental effects upon amyloidgenesis. Additionally, for future extension of the present analysis, we also performed some methodological studies using chemically modified membrane proteins. Less