英国牛津大学Lindsay A. Baker等研究人员合作发现，DNA折纸路标可通过电子冷冻断层扫描来识别细胞膜上的蛋白质。该研究于2021年2月18日发表于国际一流学术期刊《细胞》。

研究人员表示，电子冷冻照相术（cryoET）是一种电子冷冻显微术（cryoEM）形式，它通过揭示膜、病毒和细胞的天然分子细节，改变了人们对生物学功能的理解。但是，由于样品拥挤和信噪比低，从cryoET层析成像中鉴定出单个分子是一项挑战。

研究人员报道了cryoET的标记策略，该策略可以精确地识别断层图中的单个蛋白质复合物，而无需依赖金属簇。这个方法利用DNA折纸产生“分子路标”来通过荧光融合蛋白靶向目标分子，从而提供通常适用于生物表面的平台。

研究人员展示了路标折纸标签（SPOT）的体外特异性，以及它们对膜囊泡、包膜病毒和完整哺乳动物细胞外部的cryoET的适用性。 

附：英文原文

Title: DNA origami signposts for identifying proteins on cell membranes by electron cryotomography

Author: Emma Silvester, Benjamin Vollmer, Vojtěch Praák, Daven Vasishtan, Emily A. Machala, Catheryne Whittle, Susan Black, Jonathan Bath, Andrew J. Turberfield, Kay Grünewald, Lindsay A. Baker

Issue&Volume: 2021/02/18

Abstract: Electron cryotomography (cryoET), an electron cryomicroscopy (cryoEM) modality, has changed our understanding of biological function by revealing the native molecular details of membranes, viruses, and cells. However, identification of individual molecules within tomograms from cryoET is challenging because of sample crowding and low signal-to-noise ratios. Here, we present a tagging strategy for cryoET that precisely identifies individual protein complexes in tomograms without relying on metal clusters. Our method makes use of DNA origami to produce “molecular signposts” that target molecules of interest, here via fluorescent fusion proteins, providing a platform generally applicable to biological surfaces. We demonstrate the specificity of signpost origami tags (SPOTs) in vitro as well as their suitability for cryoET of membrane vesicles, enveloped viruses, and the exterior of intact mammalian cells.

DOI: 10.1016/j.cell.2021.01.033

Source: https://www.cell.com/cell/fulltext/S0092-8674(21)00076-3