Muller Daniel J
Biotechnology Center, Technische Universität Dresden, D-01307 Dresden, Germany.
Biochemistry. 2008 Aug 5;47(31):7986-98. doi: 10.1021/bi800753x. Epub 2008 Jul 11.
Cellular membranes are vital for life. They confine cells and cytosolic compartments and are involved in virtually every cellular process. Cellular membranes form cellular contacts and focal adhesions, anchor the cytoskeleton, generate energy gradients, transform energy, transduce signals, move cells, and actively form compartments to assemble different membrane proteins into functional entities. But how do cellular membranes perform these tasks? What do the machineries of cellular membranes look like, and how are they controlled and guided? Atomic force microscopy (AFM) allows the observation of biological surfaces in their native environment at a signal-to-noise ratio superior to that of any optical microscopic technique. With a spatial resolution approaching approximately 1 nm, AFM can identify the supramolecular assemblies, characteristic structure, and functional conformation of native membrane proteins. In recent years, AFM has evolved from imaging applications to a multifunctional "laboratory on a tip" that allows observation and manipulation of the machineries of cellular membranes. In the force spectroscopy mode, AFM detects interactions between two single cells at molecular resolution. Force spectroscopy can also be used to probe the local elasticity, chemical groups, and receptor sites of live cells. Other applications locate molecular interactions driving membrane protein folding, assembly, and their switching between functional states. It is also possible to examine the energy landscape of biomolecular reactions, as well as reaction pathways, associated lifetimes, and free energy. In this review, we provide a flavor of the fascinating opportunities offered by the use of AFM as a nanobiotechnological tool in modern membrane biology.
细胞膜对生命至关重要。它们界定细胞和胞质区室，几乎参与了每一个细胞过程。细胞膜形成细胞接触和粘着斑，锚定细胞骨架，产生能量梯度，转换能量，转导信号，移动细胞，并主动形成区室以将不同的膜蛋白组装成功能实体。但是细胞膜是如何执行这些任务的呢？细胞膜的机制是什么样的，它们又是如何被控制和引导的呢？原子力显微镜（AFM）能够在天然环境中观察生物表面，其信噪比优于任何光学显微镜技术。由于空间分辨率接近约1 nm，AFM能够识别天然膜蛋白的超分子组装、特征结构和功能构象。近年来，AFM已从成像应用发展成为一个多功能的“探针实验室”，能够观察和操纵细胞膜的机制。在力谱模式下，AFM能够在分子分辨率水平检测两个单细胞之间的相互作用。力谱还可用于探测活细胞的局部弹性、化学基团和受体位点。其他应用则定位驱动膜蛋白折叠、组装以及它们在功能状态之间转换的分子相互作用。还能够研究生物分子反应的能量态势，以及反应途径、相关寿命和自由能。在本综述中，我们展示了将AFM用作现代膜生物学中的纳米生物技术工具所带来的迷人机遇。
