Using mass spectrometry (MS) to obtain information about a higher order structure of protein requires that a protein's structural properties are encoded into the mass of that protein. Covalent labeling (CL) with reagents that can irreversibly modify solvent accessible amino acid side chains is an effective way to encode structural information into the mass of a protein, as this information can be read-out in a straightforward manner using standard MS-based proteomics techniques. The differential reactivity of proteins under two or more conditions can be used to distinguish protein topologies, conformations, and/or binding sites. CL-MS methods have been effectively used for the structural analysis of proteins and protein complexes, particularly for systems that are difficult to study by other more traditional biochemical techniques. This review provides an overview of the non-specific CL approaches that have been combined with MS with a particular emphasis on the reagents that are commonly used, including hydroxyl radicals, carbenes, and diethylpyrocarbonate. We describe the reagent and protein factors that affect the reactivity of amino acid side chains. We also include details about experimental design and workflow, data analysis, recent applications, and some future prospects of CL-MS methods.

中文翻译：

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使用非特异性试剂进行共价标记质谱法研究蛋白质结构和相互作用

使用质谱法 (MS) 获取有关蛋白质高级结构的信息需要将蛋白质的结构特性编码到该蛋白质的质量中。使用可以不可逆地修饰溶剂可及氨基酸侧链的试剂进行共价标记 (CL) 是将结构信息编码为蛋白质质量的有效方法，因为可以使用基于 MS 的标准蛋白质组学以直接方式读出该信息技术。蛋白质在两种或多种条件下的不同反应性可用于区分蛋白质拓扑、构象和/或结合位点。CL-MS 方法已有效地用于蛋白质和蛋白质复合物的结构分析，特别是对于其他更传统的生化技术难以研究的系统。本综述概述了与 MS 相结合的非特异性 CL 方法，特别强调了常用的试剂，包括羟基自由基、卡宾和焦碳酸二乙酯。我们描述了影响氨基酸侧链反应性的试剂和蛋白质因素。我们还包括有关实验设计和工作流程、数据分析、最近的应用以及 CL-MS 方法的一些未来前景的详细信息。