Molecular mechanism of the ATP synthase proton channel

ATP合酶质子通道的分子机制

• 批准号: 327233-2012
• 负责人: Dmitriev, Oleg
• 金额: $ 2.04万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=595212
• 关键词: Molecular; mechanism; ATP; synthase; proton

ATP synthase is a key enzyme of the energy metabolism in the vast majority of living organisms. It converts electrochemical energy stored in the form of transmembrane ion gradients into a pure chemical form of a high-energy bond in the adenosine triphosphate (ATP) molecule, which serves as a universal energy currency unit of the cell. ATP synthase functions as a molecular turbine driven by the transmembrane flow of protons through the membrane domain of the protein. The molecular mechanism of transformation of the energy of proton gradient into the kinetic energy of rotor movement is not well understood. While the high resolution structure of the rotor has been solved, the structure of the stator remains largely unknown. The long-term goal of this work is to elucidate the mechanism of proton transfer through the membrane channel of ATP synthase. We plan to analyze the structure of the proton channel using a combination of high-resolution nuclear magnetic resonance spectroscopy (NMR), X-ray crystallography, biochemical methods, and molecular modeling. We will use engineered proteins designed to model the essential structural elements of the proton channel to solve the structure by X-ray crystallography. This approach may offer an alternative to the attempts to solve the structure of the complete membrane domain of the ATP synthase, which so far have been unsuccessful. In parallel, we will continue investigation of the global fold of subunit 'a' by multidimensional NMR. The incremental structural information provided by NMR studies taken together with the large body of already available biochemical data will guide molecular modeling of the proton channel by restrained molecular dynamics until the high-resolution X-ray structure becomes available. NMR is a uniquely powerful tool for investigation of molecular dynamics of membrane proteins, as well as transient protein-lipid and protein-protein interactions. It can also provide valuable structural information, where protein crystallography fails. Investigation of subunit 'a' will advance application of high-resolution NMR to membrane proteins.

ATP合成酶是绝大多数生物体能量代谢的关键酶。它将以跨膜离子梯度形式储存的电化学能转化为三磷酸腺苷（ATP）分子中高能键的纯化学形式，ATP分子作为细胞的通用能量流通单位。ATP合酶作为分子涡轮机起作用，由质子跨膜流动通过蛋白质的膜结构域驱动。质子梯度能量转化为转子运动动能的分子机制还不清楚。虽然已经解决了转子的高分辨率结构，但定子的结构仍在很大程度上未知。本工作的长期目标是阐明质子通过ATP合酶的膜通道转移的机制。我们计划使用高分辨率核磁共振光谱（NMR），X射线晶体学，生物化学方法和分子建模的组合来分析质子通道的结构。我们将使用设计用于模拟质子通道的基本结构元素的工程蛋白质，通过X射线晶体学来解决结构问题。这种方法可以提供一种替代的尝试，以解决ATP合酶的完整的膜结构域的结构，迄今为止一直没有成功。与此同时，我们将继续调查的全球折叠的亚基'a'的多维NMR。由NMR研究提供的增量结构信息与大量已经可用的生物化学数据一起将通过受约束的分子动力学来指导质子通道的分子建模，直到高分辨率X射线结构变得可用。核磁共振是研究膜蛋白分子动力学以及瞬时蛋白质-脂质和蛋白质-蛋白质相互作用的独特强大工具。它还可以提供有价值的结构信息，蛋白质晶体学失败。对亚基a的研究将推动高分辨核磁共振在膜蛋白研究中的应用。