基于冷冻电镜无倾转成像数据的新型蛋白质原位结构解析方法

GisSPA:a New Method for in situ Protein Structural Analysis Based on Cryo-EM Single-particle-like Non-tilting Imaging Data

与体外纯化的蛋白质复合物相比,细胞内处于工作状态的蛋白质复合物往往更为完整,并且其三维结构处于完全生理的构象,这对于理解蛋白质复合物在生命活动中发挥重要功能的结构基础尤为关键,也可以为药物设计等提供更精确的靶点信息。直接在细胞内解析蛋白质复合物的三维结构也被称为蛋白质的细胞原位结构解析,而冷冻电镜电子断层重构技术是原位结构解析的关键技术,但是电子断层重构技术的序列倾转数据采集通量低、数据处理较为繁琐,并且达到准原子分辨率对样品有特殊要求,这些问题成为了限制原位结构解析分辨率和实际应用的瓶颈。近年来,一种基于单张无倾转数据的蛋白质原位结构解析方法发展迅速,可以高通量地对细胞中的蛋白质复合物进行高分辨率结构解析,本综述将分析这类方法的原理,讨论这个方法相较于传统断层重构方法的优缺点,并对蛋白质的细胞原位结构解析进行展望。希望可以通过这篇综述,帮助结构生物学科研人员更好地选择合适的工具。

Compared to in vitro purified protein complexes,protein complexes in a working state within cells are often more complete,and their three-dimensional structures are in a fully physiological conformation.This is crucial for understanding the structural basis of important functions that protein complexes play in life activities and can also provide more precise target information for drug design.The direct in situ structural analysis of protein complexes within cells is known as in situ structural analysis of proteins,and cryo-electron tomography(cryo-ET)is the key technology for in situ structural analysis.However,cryo-ET has limitations such as low data acquisition throughput for tilt series,cumbersome data processing,and special sample requirements to achieve near-atomic resolution.These issues have become bottlenecks limiting the resolution and practical application of in situ structural analysis.In recent years,a method based on the analysis of non-tilted images has developed rapidly,allowing high-throughput,high-resolution structural analysis of protein complexes within cells.This review will discuss the principles of this method,compare its advantages and disadvantages with traditional tomography,and provide an outlook on in situ structural analysis of proteins.It is hoped that this review will assist structural biologists in better choosing suitable tools.