Moreno-Madrid Francisco, Martín-González Natalia, Llauró Aida, Ortega-Esteban Alvaro, Hernando-Pérez Mercedes, Douglas Trevor, Schaap Iwan A T, de Pablo Pedro J
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid 28044, Spain.
School of Medicine, University of Washington, Seattle, WA 98195-7290, U.S.A.
Biochem Soc Trans. 2017 Apr 15;45(2):499-511. doi: 10.1042/BST20160316.
Microscopes are used to characterize small objects with the help of probes that interact with the specimen, such as photons and electrons in optical and electron microscopies, respectively. In atomic force microscopy (AFM), the probe is a nanometric tip located at the end of a microcantilever which palpates the specimen under study just as a blind person manages a walking stick. In this way, AFM allows obtaining nanometric resolution images of individual protein shells, such as viruses, in a liquid milieu. Beyond imaging, AFM also enables not only the manipulation of single protein cages, but also the characterization of every physicochemical property capable of inducing any measurable mechanical perturbation to the microcantilever that holds the tip. In the present revision, we start revising some recipes for adsorbing protein shells on surfaces. Then, we describe several AFM approaches to study individual protein cages, ranging from imaging to spectroscopic methodologies devoted to extracting physical information, such as mechanical and electrostatic properties. We also explain how a convenient combination of AFM and fluorescence methodologies entails monitoring genome release from individual viral shells during mechanical unpacking.
显微镜借助与样本相互作用的探针来表征微小物体，比如在光学显微镜和电子显微镜中分别使用的光子和电子。在原子力显微镜（AFM）中，探针是位于微悬臂梁末端的纳米级尖端，它就像盲人使用拐杖一样探测正在研究的样本。通过这种方式，原子力显微镜能够在液体环境中获得单个蛋白质外壳（如病毒）的纳米级分辨率图像。除了成像，原子力显微镜不仅能够操纵单个蛋白质笼，还能表征任何能够对固定尖端的微悬臂梁产生可测量机械扰动的物理化学性质。在本综述中，我们首先回顾一些将蛋白质外壳吸附在表面的方法。然后，我们描述几种研究单个蛋白质笼的原子力显微镜方法，从成像到致力于提取物理信息（如机械和静电性质）的光谱方法。我们还解释了原子力显微镜和荧光方法的便捷结合如何能够监测在机械解包过程中单个病毒外壳的基因组释放。
