小柯机器人

科学家开发出原子分辨率下的单颗粒冷冻电镜
2020-10-23 14:31
来源：小柯机器人

近日，英国MRC的分子生物学实验室Sjors H. W. Scheres、A. Radu Aricescu等研究人员开发出原子分辨率下的单颗粒冷冻电镜。这一研究成果于2020年10月21日在线发表在《自然》上。

研究人员使用一种新的电子源、能量过滤器和照相机来获得了人膜蛋白β3GABAA受体同源五聚体的1.7Å分辨率冷冻电镜（cryo-EM）结构。此类图谱可详细了解小分子配位、溶剂分子的可视化以及多种氨基酸的替代构象，以及有序酸性侧链和聚糖的明确构建。通过将单颗粒cryo-EM应用于小鼠去铁蛋白，这一策略产生了1.22Å分辨率的重建，从而提供了蛋白质分子的真实原子分辨率视图。而且，许多氢原子的散射电位可以在差异图中显示，进而可以直接分析氢键网络。这一技术进步与加速数据采集和改善样品质量的其他方法相结合，为在常规小分子调节剂高通量筛选和基于结构的药物发现中cryo-EM的常规应用提供了一条途径。
 
据介绍，蛋白质分子中原子的三维位置定义了它们的结构及其在生物过程中的作用。确定越精确的原子坐标，就可以得到越多的化学信息，并且可以推断出对蛋白质功能的更多机制理解。近年来，cryo-EM单颗粒分析已产生了蛋白质结构，其详细程度不断提高。然而，事实证明很难获得具有足够分辨率来可视化蛋白质中单个原子的cryo-EM重建体。
 
附：英文原文

Title: Single-particle cryo-EM at atomic resolution

Author: Takanori Nakane, Abhay Kotecha, Andrija Sente, Greg McMullan, Simonas Masiulis, Patricia M. G. E. Brown, Ioana T. Grigoras, Lina Malinauskaite, Tomas Malinauskas, Jonas Miehling, Tomasz Uchaski, Lingbo Yu, Dimple Karia, Evgeniya V. Pechnikova, Erwin de Jong, Jeroen Keizer, Maarten Bischoff, Jamie McCormack, Peter Tiemeijer, Steven W. Hardwick, Dimitri Y. Chirgadze, Garib Murshudov, A. Radu Aricescu, Sjors H. W. Scheres

Issue&Volume: 2020-10-21

Abstract: The three-dimensional positions of atoms in protein molecules define their structure and their roles in biological processes. The more precisely atomic coordinates are determined, the more chemical information can be derived and the more mechanistic insights into protein function may be inferred. Electron cryo-microscopy (cryo-EM) single-particle analysis has yielded protein structures with increasing levels of detail in recent years1,2. However, it has proved difficult to obtain cryo-EM reconstructions with sufficient resolution to visualize individual atoms in proteins. Here we use a new electron source, energy filter and camera to obtain a 1.7 resolution cryo-EM reconstruction for a human membrane protein, the β3 GABAA receptor homopentamer3. Such maps allow a detailed understanding of small-molecule coordination, visualization of solvent molecules and alternative conformations for multiple amino acids, and unambiguous building of ordered acidic side chains and glycans. Applied to mouse apoferritin, our strategy led to a 1.22 resolution reconstruction that offers a genuine atomic-resolution view of a protein molecule using single-particle cryo-EM. Moreover, the scattering potential from many hydrogen atoms can be visualized in difference maps, allowing a direct analysis of hydrogen-bonding networks. Our technological advances, combined with further approaches to accelerate data acquisition and improve sample quality, provide a route towards routine application of cryo-EM in high-throughput screening of small molecule modulators and structure-based drug discovery.

DOI: 10.1038/s41586-020-2829-0

Source: https://www.nature.com/articles/s41586-020-2829-0

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html


本期文章：《自然》：Online/在线发表

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