Janovjak Harald, Sapra K Tanuj, Kedrov Alexej, Müller Daniel J
Department. of Molecular & Cell Biology, University of California, Berkeley, 279 Life Sciences Addition, Berkeley, CA 94720-3200, USA.
Chemphyschem. 2008 May 16;9(7):954-66. doi: 10.1002/cphc.200700662.
Membrane proteins are involved in essential biological processes such as energy conversion, signal transduction, solute transport and secretion. All biological processes, also those involving membrane proteins, are steered by molecular interactions. Molecular interactions guide the folding and stability of membrane proteins, determine their assembly, switch their functional states or mediate signal transduction. The sequential steps of molecular interactions driving these processes can be described by dynamic energy landscapes. The conceptual energy landscape allows to follow the complex reaction pathways of membrane proteins while its modifications describe why and how pathways are changed. Single-molecule force spectroscopy (SMFS) detects, quantifies and locates interactions within and between membrane proteins. SMFS helps to determine how these interactions change with temperature, point mutations, oligomerization and the functional states of membrane proteins. Applied in different modes, SMFS explores the co-existence and population of reaction pathways in the energy landscape of the protein and thus reveals detailed insights into local mechanisms, determining its structural and functional relationships. Here we review how SMFS extracts the defining parameters of an energy landscape such as the barrier position, reaction kinetics and roughness with high precision.
膜蛋白参与诸如能量转换、信号转导、溶质运输和分泌等重要的生物学过程。所有生物学过程，包括那些涉及膜蛋白的过程，都由分子相互作用所驱动。分子相互作用指导膜蛋白的折叠和稳定性，决定其组装，切换其功能状态或介导信号转导。驱动这些过程的分子相互作用的连续步骤可以用动态能量景观来描述。概念性的能量景观允许追踪膜蛋白的复杂反应路径，而其修饰则描述了路径改变的原因和方式。单分子力谱（SMFS）检测、量化并定位膜蛋白内部及之间的相互作用。SMFS有助于确定这些相互作用如何随温度、点突变、寡聚化以及膜蛋白的功能状态而变化。以不同模式应用时，SMFS探索蛋白质能量景观中反应路径的共存和分布情况，从而揭示对局部机制的详细见解，确定其结构和功能关系。在此，我们综述了SMFS如何高精度地提取能量景观的定义参数，如势垒位置、反应动力学和粗糙度。
