ENZYME STRUCTURE

酶结构

• 批准号: 2573028
• 负责人: D R DAVIES
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2573028
• 关键词: Pseudomonas aeruginosa; active sites; allosteric site; exotoxins; intermolecular interaction; nicotinamide adenine dinucleotide; phosphoenolpyruvate; phosphotransferases; translation factor; tryptophan synthase

We have continued work on the high resolution structure of the bifunctional enzyme complex tryptophan synthase. This complex is a paradigm for the study of intersubunit communication and allosteric activity. We have examined the mutant betaK87T which exists as the external aldimine combined with series and with tryptophan. A series of conformational differences have been observed that provide a basis for understanding the mechanism of action and the communication between the two active sites. Domain III of Pseudomonas aeruginosa exotoxin has been crystallized and the structure determined. This domain has similar active site topology to diphtheria toxin and the toxic activity for both involve the ADP ribosylation of elongation factor II. The enzyme was previously crystallized with NAD which undergoes slow hydrolysis to give AMP and nicotinamide. We have now been able to bind a non- hydrolyzable analog of NAD that permits us to visualize the NAD binding site and have determined the crystal structure of the complex which provides a likely model for the binding of NAD and the probable association with EFII. Enzyme I of the phosphoenolpyruvate: Surgarphosphotransferase system (PTS) is the first in a series of enzymes that couple sugar transport through the membrane to phosphorylation in bacteria. The 30kD N- terminal domain of enzyme 1 of (PTS), has been crystallized and the three-dimensional structure determined. Enzyme I transfers its phosphate to the protein Hpr, and we have modeled the structure of the enzyme complexed to the protein Hpr.

我们继续致力于高分辨率结构的研究 双功能酶复合色氨酸合酶。这个综合体是一个 亚基间通讯和变构研究的范例 活动。我们已经检查了突变体 betaK87T，它作为 外用醛亚胺与系列并与色氨酸结合。 A系列 观察到的构象差异提供了基础 为了理解作用机制和沟通 两个活性位点之间。 铜绿假单胞菌外毒素结构域III已结晶 并确定了结构。该域名有类似的活跃站点 白喉毒素的拓扑结构和两者的毒性活性都涉及 延伸因子 II 的 ADP 核糖基化。该酶是 预先用 NAD 结晶，缓慢水解成 给予 AMP 和烟酰胺。我们现在已经能够绑定非 NAD 的可水解类似物，使我们能够可视化 NAD 结合位点并确定了复合物的晶体结构 这为 NAD 和可能的结合提供了一个可能的模型 与 EFII 的关联。 磷酸烯醇丙酮酸的酶 I：糖磷酸转移酶系统 (PTS) 是一系列耦合糖转运的酶中的第一个 穿过膜在细菌中磷酸化。 30kD N- (PTS) 酶 1 的末端结构域已结晶，并且 三维结构确定。酶 I 将其转移 磷酸盐结合到蛋白质 Hpr 上，我们模拟了该蛋白质的结构 与蛋白质 Hpr 复合的酶。