Factors affecting the domain movement in the bc1 complex

影响 bc1 复合体结构域移动的因素

• 批准号: 6487002
• 负责人: JASON W COOLEY
• 金额: $ 3.83万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6487002
• 关键词: Rhodospirillales; bioenergetics; computer simulation; electron spin resonance spectroscopy; enzyme complex; enzyme mechanism; enzyme model; intermolecular interaction; iron; metal complex; miscellaneous oxidoreductase; model design /development; molecular dynamics; molecular site; oxidation reduction reaction; protein structure function; site directed mutagenesis; structural biology; sulfur

DESCRIPTION: (provided by applicant) This bc1 complex and its chloroplast sister the b6f complex are essential for the establishment of the transmembrane proton gradient that is necessary for the conversion of carbohydrate and photon derived energies into high-energy chemical bonds. The bc1 complex is well studied from many organisms, with several crystal structures solved and a plethora of amino acid point mutations characterized. From this body of work it has been established that a large domain movement is critical for the catalysis of the enzyme. It is unclear however what initiates this movement and how or if it is controlled by the redox events that take place n the various regions of the complex. What is clear is that the movement of the region, which contains the paramagnetically visible [2Fe2S] cluster, is integral to the processes related to the modified Q-cycle. This cycle is the cog that allows for the efficient proton-pumping characteristic of this enzyme complex. We are proposing to utilize the orientationally dependent paramagnetic properties of the [2Fe2S] cluster in this complex in oriented samples of Rhodobacter capsulatus membranes to monitor the effects of mutations in various regions of the complex to identify the roles that various regions play in the control of the movement of the FeS protein region. We will also utilize the spectroscopic technique of electron paramagnetic resonance on oriented samples to probe the interaction of the FeS head domain and the cytochrome b containing subunit with the specific aim of identifying possible mechanisms of domain movement control during the catalytic cycle. The results obtained in this work should begin to explain the anomalous data obtained with mutations made in seemingly unrelated regions to the catalytic impairments observed as well as open the door to more advanced interpretations of mutational data in the absence of crystal structure data for the multitudes of amino acid changes made.

描述：(申请人提供)该Bc1复合体及其叶绿体 姐妹b6f复合体对于跨膜的建立是必不可少的。 碳水化合物和光子转换所必需的质子梯度 衍生出的能量转化为高能化学键。Bc1复合体很好 从许多生物体中研究出来的，解决了几个晶体结构和一个 出现过多的氨基酸点突变。从这部作品来看， 已经确定了大范围的区域移动对于催化是关键的 酶的活性。然而，目前尚不清楚是什么发起了这场运动，以及如何或是否 它受发生在不同区域的氧化还原事件控制 这个建筑群。显而易见的是，该地区的运动包含了 顺磁可见的[2Fe2S]团簇是过程中不可或缺的 与修正的Q循环有关。这个循环是一个齿轮，它允许 该酶复合体的高效质子泵特性。我们是 建议利用与取向有关的顺磁性质 在红细菌的定向样品中，该复合体中的[2Fe2S]簇 用于监测囊膜不同区域突变的影响 确定不同地区在控制中所扮演的角色 FES蛋白区域的运动。我们还将利用光谱技术 定向样品的电子顺磁共振探测技术 FeS头部结构域与细胞色素b亚基的相互作用 确定区域运动控制的可能机制的具体目标 在催化循环中。在这项工作中取得的成果应该开始 解释通过看似不相关的基因突变而获得的异常数据 区域对观察到的催化损伤以及向更多 在没有晶体结构的情况下突变数据的高级解释 大量氨基酸变化的数据。