Department of Physics, University of Bath, Bath, United Kingdom.
Biophys J. 2010 Feb 3;98(3):478-87. doi: 10.1016/j.bpj.2009.10.021.
Understanding the structural organization and distribution of proteins in biological cells is of fundamental importance in biomedical research. The use of conventional fluorescent microscopy for this purpose is limited due to its relatively low spatial resolution compared to the size of a single protein molecule. Atomic force microscopy (AFM), on the other hand, allows one to achieve single-protein resolution by scanning the cell surface using a specialized ligand-coated AFM tip. However, because this method relies on short-range interactions, it is limited to the detection of binding sites that are directly accessible to the AFM tip. We developed a method based on magnetic (long-range) interactions and applied it to investigate the structural organization and distribution of endothelin receptors on the surface of smooth muscle cells. Endothelin receptors were labeled with 50-nm superparamagnetic microbeads and then imaged with magnetic AFM. Considering its high spatial resolution and ability to "see" magnetically labeled proteins at a distance of up to 150 nm, this approach may become an important tool for investigating the dynamics of individual proteins both on the cell membrane and in the submembrane space.
了解生物细胞中蛋白质的结构组织和分布在医学研究中至关重要。由于与单个蛋白质分子的大小相比，传统荧光显微镜的空间分辨率相对较低，因此在这方面的应用受到限制。原子力显微镜 (AFM) 则通过使用专门涂覆配体的 AFM 尖端扫描细胞表面，实现单蛋白分辨率。然而，由于这种方法依赖于短程相互作用，因此它仅限于检测到 AFM 尖端直接可及的结合位点。我们开发了一种基于磁（长程）相互作用的方法，并将其应用于研究平滑肌细胞表面内皮素受体的结构组织和分布。内皮素受体用 50nm 超顺磁微珠标记，然后用磁 AFM 成像。考虑到其高空间分辨率和在 150nm 的距离上“看到”磁性标记蛋白的能力，这种方法可能成为研究细胞膜上和亚膜空间中单个蛋白质动态的重要工具。
