CAUSE & EFFECT OF DIMER ASYMMETRY IN MERCURIC REDUCTASE

原因

• 批准号: 6220327
• 负责人: SUSAN M MILLER
• 金额: $ 0.04万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6220327
• 关键词: biomedical resource; computers; informatics; technology /technique

Mercuric ion reductase catalyzes the two-electron reduction of Hg(II) to elemental mercury as the key step in bacterial detoxification of Hg(II) and organomercuricals. The enzyme is a homodimeric protein with two interfacial active sites per dimer, which extensive evidence indicates sense the redox and/or ligand state of each other. We have recently found that in the oxidative half-reaction of the enzyme with bulky thiol-liganded Hg(II) compounds, comparable to the in vivo substrate, intersubunit interactions appear to be critical in the catalytic cycle while simpler Hg(II) compounds can bypass the normal entry route and the corresponding intersubunit interactions. We use MidasPlus to identify proposed entry pathways for the small verses large Hg(II) substrates and are currently using the software to aid in the identification of additional residues along these pathways that may participate in the ligand exchange processes and represent targets for mutational analysis. We are also using the software to help visualize the electrostatic potential of the protein, especially as the liganded or redox state changes with the hypothesis that this may be a key element in the intersubunit communication. A new direction that we plan to pursue is a reengineering of the metal ion specificity of the enzyme. With our recent identification of pathways for binding, we will use the graphics to consider what types of metal ion complexes we might be able to accomodate and what changes to make to accomplish the task.

汞离子还原酶催化双电子还原 Hg(II) 转化为元素汞是细菌合成的关键步骤 Hg(II) 和有机汞的解毒。 该酶是一种 每个二聚体具有两个界面活性位点的同二聚蛋白， 大量证据表明感知氧化还原和/或配体状态 彼此。 我们最近发现，在氧化 酶与大容量硫醇配体 Hg(II) 的半反应 化合物，与体内底物、亚基间相当 相互作用似乎在催化循环中至关重要，而 较简单的 Hg(II) 化合物可以绕过正常的进入途径，并且 相应的亚基间相互作用。 我们使用 MidasPlus 来识别 建议的小与大 Hg(II) 底物的进入途径 目前正在使用该软件来帮助识别 沿着这些途径的额外残基可能参与 配体交换过程并代表突变的目标 分析。 我们还使用该软件来帮助可视化 蛋白质的静电势，特别是作为配体或 氧化还原态发生变化，假设这可能是一个关键元素 在子单元间的通信中。 我们计划的新方向 追求的是酶的金属离子特异性的重新设计。 随着我们最近对结合途径的鉴定，我们将使用 考虑我们可能是什么类型的金属离子络合物的图形 能够适应以及需要做出哪些改变才能完成任务。