“CryoEM” has come of age, enabling considerable structural insights into many facets of molecular biology. Here, we present a primer for microbiologists to understand the capabilities and limitations of two complementary cryoEM techniques for studying bacterial secretion systems. The first, single particle analysis, determines the structures of purified protein complexes to resolutions sufficient for molecular modeling, while the second, electron cryotomography and subtomogram averaging, tends to determine more modest resolution structures of protein complexes in intact cells. We illustrate these abilities with examples of insights provided into how secretion systems work by cryoEM, with a focus on type III secretion systems.

中文翻译：

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细菌分泌系统的冷冻电镜：微生物学家的入门读物

“CryoEM”已经成熟，可以对分子生物学的许多方面进行大量结构洞察。在这里，我们为微生物学家提供了一本入门书，以了解两种互补的冷冻电镜技术在研究细菌分泌系统方面的能力和局限性。第一种，单粒子分析，确定纯化蛋白质复合物的结构，其分辨率足以用于分子建模，而第二种，电子冷冻断层扫描和亚层析平均，倾向于确定完整细胞中蛋白质复合物的更适中的分辨率结构。我们通过提供有关冷冻电镜分泌系统如何工作的见解的示例来说明这些能力，重点是 III 型分泌系统。