ELECTRON-TRANSFER MEMBRANE PROTEIN COMPLEXES OF THE RESPIRATORY CHAIN

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 线粒体和细菌的呼吸链将来自底物氧化的电化学氧化还原能转化为氢离子的电化学梯度，其可用于需要能量的过程，例如ATP生成和主动运输。电子转移反应和质子转运之间的能量耦合是通过多亚基膜蛋白复合物进行的。除了它们的生物学重要性之外，这些是良好的膜蛋白，因为它们在细胞中的高丰度避免了过度表达的需要。 一个成熟的项目是细胞色素bc 1复合物（复合物III），我们已经从许多生物体中结晶出来。现在我们正在研究抑制剂和底物的结合模式，观察构象变化，并通过优化脱水和冷冻条件来推动分辨率（到目前为止为2.0）。对于复合物II，我们已经结晶了禽类酶并对晶体进行了定相，现在我们正在努力提高分辨率并解决结构。对于复合物I，我们仍在筛选结晶条件。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The respiratory chains of mitochondria and bacteria convert electrochemical redox energy from the oxidation of substrates into an electrochemical gradient of the hydrogen ion, which can be utilized for energy-requiring processes such as ATP generation and active transport. The energy coupling between electron transfer reactions and proton translocation is carried out by multi-subunit membrane protein complexes. In addition to their biological importance, these are good membrane proteins to get started with because of their high abundance in the cell which obviates the need for overexpression. A mature project is the cytochrome bc1 complex (Complex III), which we have crystallized from a number of organism. Now we are studying binding mode of inhibitors and substrates, looking at conformational changes, and pushing the resolution (2.0 ¿ so far) by optimizing dehydration and freezing conditions. For Complex II we have crystallized the avian enzyme and phased the crystals, now we are working on improving resolution and solving the structure. With Complex I we are still screening crystallization conditions.