STRUCTURAL STUDIES OF COMPLEX ENZYMES GLUTAMINE AMIDO TRANSFERASES

复合酶谷氨酰胺酰胺转移酶的结构研究

• 批准号: 6281307
• 负责人: JANET L SMITH
• 金额: $ 0.83万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 1999-08-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6281307
• 关键词: biological products; biomedical resource; proteins; radiography; structural biology

Beam time was requested to perform diffraction experiments on crystals of two glutamine amidotransferase enzymes. GMP synthetase and glutamine PRPP amidotransferase. Structures have been solved for both enzymes, and high-resolution studies will be carried out to address specific questions of biological function. The enzymes have a complex organization, with two catalytic active sites that must work in a highly coordinated way to catalyze a single biochemical transformation. Diffraction experiments have been outlined with various ligand states and mutants to probe the coupling of cataltyic activities in the two active sites of each enzyme. The aim is to measure data to the highest resolution possible. A second major aim is to measure data for the high-resolution structure of the active conformation of glutamine PRPP amidotransferase, the allosteric enzyme controlling purine biosynthesis. A structure at moderate resolution has been obtained very recently for this allosteric state. However, crystals have a unit cell edge in excess of 300
, and the diffraction limit of these crystals cannot be reached with conventional radiation. Biological significance of the projects derives from the general features of coupled catalysis by complex enzymes, and allosteric structural transitions in regulatory enzymes. All crystals can be frozen.

要求光束时间对 两个谷氨酰胺酰胺转移酶的晶体。 GMP合成酶 和谷氨酰胺PRPP酰基转移酶。 结构已解决 酶和高分辨率研究都将进行 解决生物功能的特定问题。 酶有一个 复杂的组织，具有两个必须起作用的催化活性站点 以高度协调的方式催化一种生化 转型。 衍射实验已概述 各种配体状态和突变体以探测催化的偶联 每个酶的两个活性位点的活动。 目的是 将数据测量到可能的最高分辨率。 第二个主要目标 是测量活动的高分辨率结构的数据 谷氨酰胺PRPP酰化转移酶，变构酶的构象 控制嘌呤生物合成。 中等分辨率的结构 最近已经为这种变构状态获得了。 然而， 晶体的单位细胞边缘超过300，并且衍射 这些晶体的极限无法通过常规辐射达到。 项目的生物学意义来自一般 复合酶和变构的耦合催化的特征 调节酶的结构过渡。 所有晶体都可以是 冷冻。