Structure-Based Design of Small Molecules for Aspartylglucosaminuria

基于结构的天冬氨葡萄糖胺尿小分子设计

• 批准号: 8012809
• 负责人: Hwai-Chen Guo
• 金额: $ 26.56万
• 依托单位: UNIVERSITY OF MASSACHUSETTS LOWELL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8012809
• 关键词: Acetates; Alleles; Amino Acids; Aspartylglucosaminuria; Aspartylglucosylaminase; Bicarbonates; Binding; Biochemical; Carbohydrate Linkages; Clinical; Complex; Connective Tissue; Coupled; Crystallization; Defect; Development; Disease; Early treatment; Enzyme Precursors; Enzymes; Face; Failure; Family; Foundations; Genes; Glycine; Glycoprotein Degradation Pathway; Glycoproteins; Hereditary Disease; Human; Hydrolase; Hydrolysis; Ions; Lesion; Link; Lysosomal Storage Diseases; Lysosomes; Mental Retardation; Metabolic; Metabolic Diseases; Methods; Molecular; Mutation; N-terminal; Names; Neonatal Screening; Neuraxis; Oligosaccharides; Pathogenesis; Patients; Peptides; Pharmaceutical Preparations; Proteins; Publishing; Reporting; Research Personnel; Resolution; Site; Solid; Solvents; Structure; Surface; Symptoms; Therapeutic; Threonine; Variant; base; cell type; design; functional group; glycoasparagines; inhibitor/antagonist; mutant; prevent; programs; progressive neurodegeneration; protein structure; skeletal abnormality; small molecule

DESCRIPTION (provided by applicant): Aspartylglucosaminuria (AGU) is a lysosomal storage disease caused by a metabolic disorder in glycoprotein degradation. AGU results in accumulation of glycoasparagines in the lysosomes of virtually all cell types, with severe clinical symptoms such as progressive neurodegeneration and mental retardation, coarse facial features, skeletal abnormalities, and connective tissue lesions. AGU mutations occur in the gene for glycosylasparaginase (GA), a lysosomal enzyme required to hydrolyze glycoasparagines. AGU has been reported worldwide, with 26 different AGU alleles found so far, but still no treatment available for this disease. However, during the past few years, there has been significant progress in the identification and characterization of AGU causative mutations. Thus development of an effective AGU therapy would make this genetic disease amenable to newborn screening for an early treatment. Our crystallographic studies on GA reveal that a surface loop (named precursor P-loop) blocks the catalytic center of mature hydrolase. Autoproteolysis is thus required to remove this P-loop in order to open up the catalytic center. Nonetheless, AGU mutations cause misprocessing and mistargeting of GA precursors, thus prevents their autoactivation for the hydrolase activity. High-resolution structural studies of GA and AGU molecules will greatly enhance our understanding of the structural consequences of these AGU mutations but have so far been hampered by the inability to obtain sufficient amounts of highly purified human GA. Nonetheless, we have overcome this hurdle by purifying and crystallizing bacterial GA, which has been demonstrated to have identical structural features and use the same mechanism to autoactivate its hydrolase activity. Our preliminary results indicate that small molecules with structures similar to glycine can enhance autoproteolytic and hydrolase activity of AGU mutants. Building on our recent progress on GA autoprocessing, we propose in this application to 1) characterize molecular pathogenesis of AGU mutations; 2) push forward our structural and mechanistic studies of GA autoproteolytic activation; 3) study structural consequences of AGU mutations; and 4) develop small molecules to stimulate autoprocessing of AGU molecules. The broad, long- term objective of this application is to develop small molecules as therapeutics to ameliorate the AGU misprocessing and mistargeting defect and thus alleviate the suffering of AGU patients and their families.

描述（由申请人提供）：Aspartyl-葡萄糖粉（AGU）是由糖蛋白降解中的代谢疾病引起的溶酶体储存疾病。 AGU导致在几乎所有细胞类型的溶酶体中积累甘草叠素，具有严重的临床症状，例如进行性神经退行性和智力低下，粗面部特征，骨骼异常和结缔组织病变。 AGU突变发生在糖基半冬糖苷酶（GA）的基因中，这是一种水解甘草酶的溶酶体酶。据报道，AGU在世界范围内据报道，到目前为止发现了26个不同的AGU等位基因，但仍未使用该疾病。但是，在过去的几年中，在AGU致病突变的鉴定和表征方面取得了重大进展。因此，开发有效的AGU疗法将使这种遗传疾病适合于新生儿筛查以进行早期治疗。我们对GA的晶体学研究表明，表面环（命名为前体P-Loop）阻断了成熟水解酶的催化中心。因此，需要自动溶解以去除此P环以打开催化中心。尽管如此，AGU突变会导致GA前体的错误处理和误解，从而阻止其自动激活水解酶活性。 GA和AGU分子的高分辨率结构研究将大大增强我们对这些AGU突变的结构后果的理解，但到目前为止，由于无法获得足够量的高度纯化的人类GA而受到阻碍。尽管如此，我们通过纯化和结晶细菌GA来克服这一障碍，该障碍已被证明具有相同的结构特征，并使用相同的机制自动激活其水解酶活性。我们的初步结果表明，具有类似于甘氨酸的结构的小分子可以增强AGU突变体的燃料溶解和水解酶活性。在我们最近在GA自动加工方面的进展的基础上，我们在此应用中建议1）表征AGU突变的分子发病机理； 2）推动我们对GA自溶解激活的结构和机械研究； 3）研究AGU突变的结构后果； 4）开发小分子以刺激AGU分子的自动化。该应用的广泛长期目标是开发小分子作为治疗药，以改善AGU错误处理和误入性缺陷，从而减轻AGU患者及其家人的痛苦。