德国欧洲生物学实验室Julia Mahamid等研究人员合作开发出优化多颗粒冷冻电镜结果的软件工具。2021年2月4日，国际知名学术期刊《自然—方法学》在线发表了这一成果。

研究人员报道了软件工具M，可为冷冻电镜（cryo-EM）数据建立基于参照的多颗粒优化框架，并将综合的空间变形模型与电子光学像差的计算机校正相结合。M为帧系列和断层扫描倾斜系列数据提供了统一的优化框架。结果表明，倾斜系列数据可以提供与纯化蛋白样品上的帧系列数据相同的分辨率，这表明对比步骤不再限制从层析成像数据中获得的分辨率。与Warp和RELION结合使用时，M可将完整细菌细胞内结合抗生素的70S核糖体解析至氨基酸残基水平。

这项工作提供了可促进细胞结构生物学的计算工具。

据介绍，cryo-EM能够确定体外和细胞内的大分子结构。除了排列单个粒子外，在曝光过程中准确记录样本运动和三维变形对于实现高分辨率重建也至关重要。

附：英文原文

Title: Multi-particle cryo-EM refinement with M visualizes ribosome-antibiotic complex at 3.5 Å in cells

Author: Dimitry Tegunov, Liang Xue, Christian Dienemann, Patrick Cramer, Julia Mahamid

Issue&Volume: 2021-02-04

Abstract: Cryo-electron microscopy (cryo-EM) enables macromolecular structure determination in vitro and inside cells. In addition to aligning individual particles, accurate registration of sample motion and three-dimensional deformation during exposures are crucial for achieving high-resolution reconstructions. Here we describe M, a software tool that establishes a reference-based, multi-particle refinement framework for cryo-EM data and couples a comprehensive spatial deformation model to in silico correction of electron-optical aberrations. M provides a unified optimization framework for both frame-series and tomographic tilt-series data. We show that tilt-series data can provide the same resolution as frame-series data on a purified protein specimen, indicating that the alignment step no longer limits the resolution obtainable from tomographic data. In combination with Warp and RELION, M resolves to residue level a 70S ribosome bound to an antibiotic inside intact bacterial cells. Our work provides a computational tool that facilitates structural biology in cells. The software M establishes a reference-based multi-particle refinement framework for cryo-EM data. Combined with CTF correction and map denoising, M enables residue-level structure determination inside cells.

DOI: 10.1038/s41592-020-01054-7

Source: https://www.nature.com/articles/s41592-020-01054-7