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: 6626142
• 负责人: JASON W COOLEY
• 金额: $ 4.64万
• 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/6626142
• 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）此bc1复合物及其叶绿体 姐妹b6f复合物对于跨膜的建立是必需的。 碳水化合物和光子转化所必需的质子梯度 将能量转化为高能化学键。bc1复合体是良好的 研究了许多生物体，解决了几个晶体结构， 大量的氨基酸点突变特征。从这一系列的工作中， 已经确定，大的畴运动对于催化是关键的 的酶。然而，尚不清楚是什么启动了这一运动，以及如何或是否启动了这一运动。 它是由发生在不同区域的氧化还原事件控制的， 复杂的。很明显，该地区的运动，其中包括 顺磁性可见的[2Fe2S]团簇，是不可或缺的过程 与修改后的Q周期相关。这个循环是齿轮， 这种酶复合物的高效质子泵送特性。我们 建议利用取向依赖的顺磁特性， 红细菌定向样品中[2Fe2S]簇 囊膜，以监测突变的影响，在不同地区的 复杂的，以确定各地区发挥的作用，在控制 FeS蛋白区域的移动。我们还将利用光谱 定向样品上的电子顺磁共振技术来探测 FeS头部结构域和含有细胞色素B的亚基与 确定域运动控制的可能机制的具体目标 在催化循环中。这项工作所取得的成果应开始， 解释在看似无关的基因突变中获得的异常数据， 观察到的催化障碍的区域，以及打开大门， 在缺乏晶体结构的情况下对突变数据的高级解释 大量氨基酸变化的数据。