Structure and Function of Enzymes in Fatty Acid Oxidation

脂肪酸氧化酶的结构和功能

基本信息

批准号：
8706154
负责人：
JUNG JA P. KIM
金额：
$ 38.09万
依托单位：
MEDICAL COLLEGE OF WISCONSIN
依托单位国家：
美国
项目类别：
财政年份：
1982
资助国家：
美国
起止时间：
1982-03-01 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8706154
关键词：
Acetyl Coenzyme A Active Sites Acyl CoA Dehydrogenases Acyl Coenzyme A Affect Agonist Amino Acids Binding Biochemical Cardiomyopathies Cells Chemicals Child Choline Cleaved cell Clinical Coenzyme A Complex Crystallization Development Diabetes Mellitus Diet Disease Electron Spin Resonance Spectroscopy Electron Transport Electron transfer flavoprotein Electrons Enoyl-CoA Hydratase Enzymes Escherichia coli Etiology Exercise Failure to Thrive Family Fasting Fatty Acids Flavins Flavoproteins Goals Health Heart Hepatocyte Human Human Activities Human body Inborn Genetic Diseases Inherited Inner mitochondrial membrane Investigation Kidney Left Ligand Binding Ligands Light Liver Long-Chain-Acyl-CoA Dehydrogenase Mass Spectrum Analysis Membrane Metabolic Metabolic Diseases Metabolic syndrome Metabolism Methods Mitochondria Mitochondrial Diseases Molecular Conformation Movement Multienzyme Complexes Muscle Muscle Cells Mutation Myocardium Myopathy NADP Neonatal Screening Non-Insulin-Dependent Diabetes Mellitus Obesity Oxidants Oxidoreductase Physiological Play Pregnancy Process Protein Binding Proteins Reaction Recombinant Proteins Resolution Respiratory Chain Role Series Structure Sudden infant death syndrome System Testing Therapeutic Time Very Long Chain Fatty Acid X-Ray Crystallography acyl-CoA dehydrogenase base clinical phenotype crosslink dehydrogenation design diagnosis design dimethylglycine dehydrogenase electron donor electron-transferring-flavoprotein dehydrogenase fatty acid oxidation feeding heart cell improved inhibitor/antagonist insight long chain fatty acid member mitochondrial membrane novel oxidation polypeptide protein protein interaction skeletal thioester young adult

项目摘要

DESCRIPTION (provided by applicant): Fatty acid ?-oxidation is the major energy-producing process in the liver, heart, and muscle. It is carried out by a series of four reactions that successively cleave acetyl-CoA from fatty acyl-CoA. The rate of this process can be altered by diet (fed/fasting), physiological status (pregnancy), or diseases (diabetes). The first of the four reactions in this process is initiated by a family of flavoproteins, acyl-CoA dehydrogenases (ADs). Electron transfer from ADs to the mitochondrial OXPHOS chain is catalyzed by electron transfer flavoprotein (ETF) and the membrane-bound ETF-ubiquinoneoxidoreductase (ETF-QO). There are at least seven soluble ADs for catalyzing short chain acyl-CoAs, and two membrane-bound ADs specific for long chain fatty acyl-CoAs, very long chain AD (VLCAD) and ACAD9. The three remaining reactions of ?- oxidation for long chain fatty acids are carried out by the trifunctional protein (TFP), a membrane-bound multienzyme complex. Inborn errors of fatty acid oxidation have emerged as an increasing health problem and now represent the most common group of disorders identified through expanded newborn screening, affecting 2-3/1,000 babies born nationwide. These disorders present sudden infant death syndrome, cause cardiomyopathy, and are the most common cause of skeletal myopathy in older children and young adults. Recently ACAD9 has been shown to be essential for the assembly of Complex I, the largest and most complicated enzyme (~980 kDa with 45 subunits) among the five OXPHOS complexes. Very little is known concerning the mechanism of the assembly process of this important enzyme. Disorders of the mitochondrial OXPHOS system are the most common of inborn metabolic diseases, resulting in a wide variety of clinical phenotypes ranging from exercise intolerance to failure to thrive. We have determined the crystal structures of all but one of the soluble ADs, as well as one membrane-bound AD (VLCAD), ETF, and ETF-QO. The proposed investigations are focused on three membrane-bound enzymes, VLCAD, ACAD9, and TFP, and interactions of ETF with its electron transfer partners, including ADs, dimethylglycine dehydrogenase (DD), and ETF-QO. DD functions in choline metabolism and is not a member of the AD family, but donates electrons to ETF. Specific Aims are: 1) Structural studies of human TFP by X-ray crystallography to understand how its three distinct active sites communicate with each other; 2) Studies of VLCAD, including a) studies of clinical mutations, and b) to determine the orientation of VLCAD on the mitochondrial membrane and interactions with TFP and ETF by EPR spectroscopy; 3) studies of ACAD9 to determine the biochemical/structural basis for its unique role in mitochondrial Complex I assembly; and 4) to investigate the domain movement of ETF and its interactions with three representative electron donors (medium chain acyl-CoA dehydrogenase, VLCAD, and DD) and with its electron acceptor, ETF-QO.

描述（由申请人提供）：脂肪酸？氧化是肝脏，心脏和肌肉中主要产生能量的过程。它是通过一系列四个反应进行的，这些反应依次从脂肪酰基辅酶A裂解乙酰辅酶A。饮食（喂养/禁食），生理状况（妊娠）或疾病（糖尿病）可以改变此过程的速度。四个中的第一个在此过程中的反应是由黄蛋蛋白，酰基-COA脱氢酶（ADS）引发的。电子从AD到线粒体Oxphos链的转移是通过电子转移黄蛋蛋白（ETF）和结合膜结合的ETF-ubiquinoneoxidoxiductase（ETF-QO）催化的。至少有七个可催化短链酰基辅助的可溶性广告，以及两个针对长链脂肪酰基辅助烟灰，非常长的链条AD（VLCAD）和ACAD9的膜结合的广告。长链脂肪酸的氧化的剩余反应是由三官能蛋白（TFP）进行的，这是一种膜结合的多酶复合物。天生的脂肪酸氧化错误已成为越来越多的健康问题，现在代表了通过扩大的新生儿筛查确定的最常见的疾病群体，影响了全国生于全国的2-3/1,000名婴儿。这些疾病呈现出婴儿猝死综合征，导致心肌病，并且是大儿童和年轻人骨骼肌病的最常见原因。最近，Acad9被证明对于五个OXPHOS配合物中最大，最复杂的酶（〜980 kDa和45个亚基）是必不可少的。关于这种重要酶的组装过程的机制知之甚少。线粒体Oxphos系统的疾病是最常见的天生代谢疾病，导致各种各样的临床表型，从运动不耐受到不蓬勃发展。我们已经确定了除一个可溶性广告以外的所有晶体结构，以及一个膜结合的AD（VLCAD），ETF和ETF-QO。拟议的研究集中于三种结合膜结合的酶，VLCAD，ACAD9和TFP，以及ETF与其电子转移伙伴的相互作用，包括ADS，二甲基甘氨酸脱氢酶（DD）和ETF-QO。 DD在胆碱代谢中起作用，不是AD家族的成员，而是向ETF捐赠电子。具体目的是：1）X射线晶体学对人类TFP的结构研究，以了解其三个不同的活性位点如何相互通信； 2）VLCAD的研究，包括a）临床突变的研究，b）确定VLCAD在线粒体膜上的取向以及通过EPR光谱与TFP和ETF相互作用； 3）研究的研究确定其在线粒体复合物I组装中的独特作用的生化/结构基础； 4）研究ETF的结构域运动及其与三个代表性电子供体（中链酰基-COA脱氢酶，VLCAD和DD）以及其电子受体ETF-QO的相互作用。