CRYSTAL STRUCTURE OF YEAST NAD-SPECIFIC ISOCITRATE DEHYDROGENASE

酵母 NAD 特异性异柠檬酸脱氢酶的晶体结构

• 批准号: 7726261
• 负责人: Peter JOHN HART
• 金额: $ 0.55万
• 依托单位: BROOKHAVEN SCIENCE ASSOC-BROOKHAVEN LAB
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-18 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7726261
• 关键词: Affinity; Anodes; Attenuated; Binding; Binding Sites; Citrate; Citrates; Citric Acid Cycle; Computer Retrieval of Information on Scientific Projects Database; Condition; Decarboxylation; Enzymatic Biochemistry; Enzymes; Funding; Future; Glycolysis; Glycolysis Pathway; Grant; Institution; Isocitrate Dehydrogenase; Isocitrates; Ligand Binding; Mitochondria; Multienzyme Complexes; Mutagenesis; NADH; Nicotinamide adenine dinucleotide; Pathway interactions; Production; Rate; Regulation; Relative (related person); Research; Research Personnel; Resources; Roentgen Rays; Site; Source; Structure; Tricarboxylic Acids; United States National Institutes of Health; Yeasts; alpha ketoglutarate; isocitrate; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The oxidative decarboxylation of isocitrate to alpha-ketoglutarate catalyzed by mitochondrial NAD-specific isocitrate dehydrogenases is a rate limiting step in the tricarboxylic acid (TCA) cycle. The affinity of the yeast enzyme (IDH) for isocitrate is allosterically regulated, positively by AMP and negatively by ATP and NADH. This allosteric control has been proposed to contribute to inverse regulation of rates of energy production by oxidative pathways and by glycolysis. Thus, under conditions of energy sufficiency, i.e. when relative cellular ratios of [ATP]/[AMP] and of [NADH]/[NAD] are high, flux through the TCA cycle would be attenuated at the level of IDH, rates of glycolysis would increase, and the tricarboxylic acids, citrate and isocitrate, would be diverted into biosynthetic pathways. Yeast IDH is an octamer composed of four IDH1 and four IDH2 subunits. IDH1 (M.W. = 38,001) and IDH2 (M.W. = 37,755) share 42% sequence identity. Results of targeted mutagenesis studies suggest that the IDH2 subunit contains catalytic isocitrate/Mg2+ and NAD binding sites, whereas homologous sites in the IDH1 subunit function in cooperative binding of isocitrate and in binding of the allosteric activator AMP. An understanding of the oligomeric structure of IDH would thus illuminate relationships between homologous catalytic and regulatory ligand binding sites. We have produced crystals of IDH that diffract to 3.2¿¿¿ on a Rigaku FR-D rotating anode X-ray source. We anticipate that the determination of the oligomeric arrangement of IDH in the crystal structure will reveal the mode of allosteric control of this complex enzyme. Additionally, the information provided by the structure will direct future experiments investigating IDH enzymology.

该副本是使用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这是调查员的机构。 线粒体NAD特异性异位酸脱氢酶催化α-酮戊二酸α-酮戊二酸的氧化脱羧化是三羧酸（TCA）循环中的速率限制步骤。酵母酶（IDH）对等酸的亲和力在变构中受到AMP的阳性调节，而ATP和NADH对否定性。已经提出，这种变构控制有助于通过氧化途径和糖酵解对能量产生速率的反向调节。在能及能力条件下，即[ATP]/[AMP]和[NADH]/[NAD]的相对细胞比率很高时，在IDH的水平上会减弱通量的通量，糖酵解的速率将会增加，而三核酸，三核酸，柠檬酸盐和异位酸盐均会划分，将其划分。酵母IDH是一个由四个IDH1和四个IDH2亚基组成的八聚体。 IDH1（M.W. = 38,001）和IDH2（M.W. = 37,755）共享42％的序列身份。靶向诱变研究的结果表明，IDH2亚基包含催化异位酸/MG2+和NAD结合位点，而IDH1亚基功能中的同源性位点在等二脑的合作结合和异蜂巢激活剂AMP的结合中。因此，对IDH的寡聚结​​构的理解将照亮同源催化和调节配体结合位点之间的关系。 我们已经在Rigaku Fr-D旋转阳极X射线源上产生了IDH的晶体，将衍射为3.2 ??。我们预计确定IDH在晶体结构中的寡聚排列将揭示这种复合酶的变构控制方式。此外，结构提供的信息将指导研究IDH酶学的未来实验。