Characterization of prion protein conformational changes

朊病毒蛋白构象变化的表征

• 批准号: 7663763
• 负责人: VALERIE D DAGGETT
• 金额: $ 27.58万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7663763
• 关键词: Address; Affect; Animals; Base Sequence; Behavior; Blood; Body Temperature; Bovine Spongiform Encephalopathy; Brain; Cattle; Chickens; Chronic Wasting Disease; Collaborations; Creutzfeldt-Jakob Syndrome; Deer; Deposition; Disease; Docking; Environment; Family suidae; Fatal Familial Insomnia; Food Supply; GPI Membrane Anchors; Glycoproteins; Goals; Hamsters; Heterogeneity; Human; In Vitro; Kuru; Lead; Link; Lipid Bilayers; Membrane; Membrane Lipids; Modeling; Molecular Models; Molecular Probes; Mus; Organ; Patients; Polysaccharides; PrPSc Proteins; Prion Diseases; Prions; Process; Proteins; Rare Diseases; Research Personnel; Resistance; Resolution; Scrapie; Sheep; Simulate; Structure; Symptoms; Testing; Turtles; United States National Institutes of Health; Variant; Water; base; conformer; design; glycosylation; in vivo; molecular dynamics; molecular modeling; mutant; programs; protein aggregate; protein expression; protein protein interaction; research study; simulation; single molecule; transmission process

DESCRIPTION (provided by applicant): Transmissible spongiform encephalopathies (TSEs) are caused by a conformational change in the prion protein (PrP), which is a membrane-associated, glycoprotein. TSEs, or prion diseases, include Creutzfeldt-Jakob disease, fatal familial insomnia and Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy in cattle, and chronic wasting disease in deer and elk. While rare, these diseases are always fatal. Given that they are also transmissible, they don't necessarily just affect the afflicted patient or animal: the human forms represent a threat to blood and organ recipients and the animal forms are a threat to our food supply. The central hypothesis in prion disease is that it is a protein-only disease, whereby the prion protein is the only agent necessary for propagation and transmission. In the disease process, the prion protein converts from its primarily helical, cellular form (PrPC) to a conformer rich in beta-structure with retention of most of the helical structure (PrPSc). PrPSc aggregates, causes disease, and is infectious. While most studies focus on just the protein, PrP's N-linked glycans influence PrP expression, distribution, and deposition in the brain, which in turn determines patient symptoms. Unfortunately it has proved impossible to obtain high-resolution structural information for the conversion process and corresponding disease-associated conformers from experiment. Consequently, our hypothesis is that all-atom molecular dynamics simulations will provide testable models (to be tested in collaboration with Dr. Byron Caughey, NIH RML) for the conversion process, species barriers, the infectious oligomers, and the effect of glycosylation and the lipid membrane on the process. Specifically, we will: ?Perform multiple molecular dynamics (MD) simulations of the cellular prion protein (PrPC) from different species (human, bovine, hamster, ovine, mouse, chicken, turtle, pig and elk) in water at neutral and low pH (low pH triggers the conformational change to PrPSc both in vivo and in vitro) ?Perform MD simulations of more biologically relevant protein constructs by including glycans, the GPI anchor, and the membrane environment at neutral and low pH to assess their effect on conversion ?Construct molecular models for the infectious, toxic protofibrillar oligomers (not fibrils) of PrPSc and perform MD simulations of these constructs as well as hetero-oligomers (for example bovine PrPSc + human PrPC) to investigate species barriers.

描述（由申请人提供）：可传播的海绵状脑病（TSE）是由prion蛋白（PRP）的构象变化引起的，该蛋白（PRP）是膜相关的糖蛋白。 TSE或prion疾病包括克鲁特兹菲尔特 - 贾科布疾病，人类的致命家族失眠和库鲁，绵羊的小crap，牛的牛海绵状脑病，以及鹿和麋鹿的慢性浪费疾病。虽然很少见，但这些疾病总是致命的。鉴于它们也可以传播，因此它们不一定仅仅影响受伤的患者或动物：人类形式代表了对血液和管风琴接受者的威胁，而动物形式对我们的粮食供应构成威胁。 Prion疾病中的中心假设是它是一种仅蛋白质疾病，因此，prion蛋白是传播和传播所需的唯一药物。在疾病过程中，prion蛋白从其主要的螺旋形式的细胞形式（PRPC）转化为富含β结构的构象异构体，并保留大多数螺旋结构（PRPSC）。 PRPSC骨料，引起疾病，并具有感染力。虽然大多数研究仅关注蛋白质，但PRP的N连锁聚糖会影响大脑中的PRP表达，分布和沉积，这反过来决定了患者的症状。不幸的是，事实证明，无法获得转化过程的高分辨率结构信息，并从实验中获得相应的疾病相关构象异构体。因此，我们的假设是全原子分子动力学模拟将提供可测试的模型（将与Byron Caughey博士，NIH RML合作进行测试），用于转化过程，物种屏障，感染性低聚物，以及糖基化的效果，以及该过程中的脂质膜。具体来说，我们将： ？对来自中性和低pH的水中的不同物种（人，牛，仓鼠，小鼠，鸡肉，鸡，鸡肉，猪和麋鹿）的细胞prion蛋白（PRPC）进行多个分子动力学（MD）模拟 通过包括Glycans，GPI锚和中性和低pH值的膜环境，对更相关的蛋白质结构进行MD模拟，以评估其对转化的影响 ？构建分子模型，用于PRPSC的感染性，有毒原纤维低聚物（而不是原纤维），并对这些构建体以及异性盐（例如Bovine PRPSC +人类PRPC）进行MD模拟来研究物种屏障。