TRANSCARBOXYLASE 13S STRUCTURE AND CO2 INTERMEDIATES

转羧酶 13S 结构和 CO2 中间体

• 批准号: 2388065
• 负责人: PAUL R CAREY
• 金额: $ 26.05万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2388065
• 关键词: Raman spectrometry; aminoacid metabolism; bicarbonates; biotin; carbon dioxide; carboxyltransferase /carbamoyltransferase; chemical kinetics; infrared spectrometry; interferometry; nuclear magnetic resonance spectroscopy; phosphates; protein structure function; quantum chemistry

DESCRIPTION: Biotin containing enzymes are found in all organisms and catalyze key steps in metabolic pathways. In humans, deficiencies in these enzymes can have serious, or catastrophic, consequences. In spite of continuing mechanistic and medical interest, little is known of the detailed structure and chemistry of this closely related family of proteins. The strategic goals of this research are to define the atomic details of the 1.3 S subunit of transcarboxylase (TC) and of its intermediate which has a carboxylate group transiently bound to the biotin cofactor. Multidimensional heteronuclear NMR will be used to solve the structures of the holo- and apo- 1.3 S protein in solution. The proteins will be labeled with 15N and/or 13C. The properties of the biotin co-factor on the protein, which relate to its function as a carboxylate acceptor, transporter and donor, will be elucidated by Raman and FTIR difference spectroscopies and by NMR. The structure and electron distribution in the carboxy-biotin complex on the 1.3 S subunit will be determined also by a combination of vibrational and NMR spectroscopies. In addition, changes in the protein s structure upon biotin carboxylation will be probed by NMR. Recent FTIR data indicate that after the CO2 moiety leaves the biotin ring on 1.3S via spontaneous decarboxylation, it remains associated witht he protein as an, as yet, uncharacterized complex. The complex will be identified using virbational spectroscopic techniques and NMR, in addition to experiments aimed at trapping the complex in a stable form using CH2N2. As a test of catalytic competence, the novel complex will be reacted with pyruvate in the presence of the 5S subunit to see if oxalacetate is formed. Vibrational spectroscopic analysis of biotin model compounds, of carboxy-biotin compounds and their isotopomers will be combined with quantum mechanical calculations to provide a basis for interpreting the data for biotin and carboxy-biotin on 1.3S.

描述：所有生物体中都含有生物素酶 催化代谢途径的关键步骤。 人类缺乏这些 酶可能会产生严重或灾难性的后果。 尽管 持续的机械和医学兴趣，但对其详细信息知之甚少 这个密切相关的蛋白质家族的结构和化学。 这 这项研究的战略目标是定义 1.3 的原子细节 转羧酶 (TC) 及其中间体的 S 亚基，具有 羧酸酯基团短暂地与生物素辅助因子结合。 多维异核核磁共振将用于解析 溶液中的 Holo- 和 apo- 1.3 S 蛋白。 蛋白质将被标记 15N 和/或 13C。 生物素辅因子对蛋白质的特性， 这与其作为羧酸受体、转运蛋白的功能有关 供体，将通过拉曼和 FTIR 差异光谱以及通过 核磁共振。 羧基-生物素复合物的结构和电子分布 1.3 S亚基也将由振动和振动的组合决定 核磁共振波谱。 此外，蛋白质结构的变化 将通过 NMR 探测生物素羧化作用。 最近的 FTIR 数据表明，CO2 部分离开生物素环后 通过自发脱羧作用在 1.3S 上，它仍然与他相关 蛋白质作为一种尚未表征的复合物。 该综合体将是 此外，还使用振动光谱技术和核磁共振进行了鉴定 旨在使用 CH2N2 以稳定形式捕获复合物的实验。 作为催化能力的测试，新型配合物将与 在 5S 亚基存在的情况下检测丙酮酸，看看是否形成草乙酸。 生物素模型化合物的振动光谱分析 羧基生物素化合物及其同位素异构体将与量子结合 机械计算为解释数据提供基础 1.3S 上的生物素和羧基生物素。