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Mechanisms of glutamate dehydrogenase allostery

谷氨酸脱氢酶变构机制

基本信息

批准号：
7481097
负责人：
THOMAS JAMES. SMITH
金额：
$ 34.53万
依托单位：
DONALD DANFORTH PLANT SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-09-30 至 2010-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7481097
关键词：
Affect Algorithms Allosteric Regulation Allosteric Site Amino Acids Animal Structures Animals Bacteria Beta Cell Binding Binding Sites Biochemistry Bos taurus Canned Foods Catechin Cattle Chemistry Child Coenzymes Collaborations Communication Complex Crystallography Deamination Diethylstilbestrol Disease Enzymes Evolution Family Glucose Glutamate Dehydrogenase Glutamates Glutamine Goals Grant Guanosine Triphosphate Homeostasis Human Hyperammonemia Hyperinsulinism Individual Insulin Kinetics Laboratories Lead Leucine Life Ligand Binding Ligands Link Location Mediating Mitochondria Modeling Molecular Biology Mutate Mutation Non-Insulin-Dependent Diabetes Mellitus Normal tissue morphology Numbers Organism Palmitoyl Coenzyme A Pancreas Pathology Personal Satisfaction Plant Roots Play Poison Property Protein Subunits Regulation Research Personnel Role Signaling Molecule Simulate Structure Syndrome Techniques Testing Tetrahymena Tissues alpha ketoglutarate design gain of function insulin secretion mutant novel plant fungi programs

项目摘要

Glutamate dehydrogenase (GDH) is an ancient enzyme found in all living organisms. The underlying chemistry of the reversible oxidative deamination of glutamate to 2-oxoglutarate catalyzed by this enzyme has remained unchanged through the epochs. However, GDH from the animal kingdom is allosterically regulated by a large number compounds while the enzyme from other kingdoms is completely unregulated. Through our individual and collaborative efforts, we have determined the structures of animal GDH complexed with several of these allosteric regulators and have models for how allostery is exacted. We have also shown the importance of GDH regulation by our finding that mutations that affect GTP inhibition are the root cause of the hyperinsulinism/hyperammonemia (HI//HA) syndrome in children. Furthermore, we have shown that GDH is involved in both glucose and leucine stimulated secretion of insulin from normal pancreatic tissue. We propose that this regulation of insulin homeostasis is due to GDH-mediated controlof intracellular signaling molecule, glutamine. It is therefore apparent that understanding the allosteric regulation of GDH is crucial to understanding insulin homeostasis. To that end, this proposal aims to use a combination of techniques to understand where these various regulators bind and how they modulate enzymatic activity. We will also further analyze some of HI/HA mutants to better understand the pathology of this life-threatening disorder. Perhaps most exciting is that we have leveraged our understanding of GDH to discover a family of new, non-toxic compounds that act via GDH and can potentially treat both HI/HA and type II diabetes. Finally, we have shown that the GDH from Ciliates is an evolutionary 'missing link' between animals and the other kingdoms. By further studying this form of GDH we will elucidate animal allostery by better understanding how and why it evolved. Together, these studies will not only answer fundamental questions as to how protein subunits communicate with each other during allostery but will solidify our hypothesis that allosteric regulation of GDH plays a critical role in insulin homeostasis.

谷氨酸脱氢酶（GDH）是一种存在于所有生物体中的古老酶。底层谷氨酸酶催化的谷氨酸可逆氧化脱氨化学在各个时代都保持不变。然而，来自动物王国的GDH是变构的，受大量化合物调节，而来自其他界的酶完全不受调节。通过我们个人和合作的努力，我们已经确定了动物GDH的结构与这些变构调节剂中的几种复合，并具有如何进行变构的模型。我们有通过我们的发现，影响GTP抑制的突变是GDH调节的重要性，儿童高胰岛素血症/高氨血症（HI//HA）综合征的根本原因。此外，我们还表明GDH参与葡萄糖和亮氨酸刺激的胰岛素分泌，胰腺组织我们认为，这种胰岛素稳态的调节是由于GDH介导的对胰岛素分泌的控制。胞内信号分子谷氨酰胺。因此，很明显，理解GDH的变构调节对于理解胰岛素稳态为此，本建议旨在使用技术组合来了解这些不同的调节剂在哪里结合以及它们如何调节酶活性。我们还将进一步分析一些HI/HA突变体，以更好地了解这种危及生命的疾病的病理学。也许最令人兴奋的是，我们已经利用我们对GDH的理解，发现了一个新的，无毒的这些化合物通过GDH起作用，并且可以潜在地治疗HI/HA和II型糖尿病。我们终于有表明来自纤毛虫的GDH是动物和其它界之间进化上的“缺失环节”。通过进一步研究这种形式的GDH，我们将阐明动物变构更好地了解如何和为什么它进化了总之，这些研究不仅将回答蛋白质亚基如何在变构过程中，GDH与其他细胞相互联系，但这将巩固我们的假设，即GDH的变构调节在胰岛素稳态中起着关键作用。