Free radical‐initiated peptide sequencing (FRIPS) has recently been introduced as an analytical strategy to create peptide radical ions in a predictable and effective way by collisional activation of specifically modified peptides ions. FRIPS is based on the unimolecular dissociation of open‐shell ions and yields fragments that resemble those obtained by electron capture dissociation (ECD) or electron transfer dissociation (ETD). In this review article, we describe the fundamentals of FRIPS and highlight its fruitful combination with chemical cross‐linking/mass spectrometry (MS) as a highly promising option to derive complementary structural information of peptides and proteins. FRIPS does not only yield exhaustive sequence information of cross‐linked peptides, but also defines the exact cross‐linking sites of the connected peptides. The development of more advanced FRIPS cross‐linkers that extend the FRIPS‐based cross‐linking/MS approach to the study of large protein assemblies and protein interaction networks can be eagerly anticipated.

中文翻译：

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基于自由基引发的肽测序（FRIPS）的交联剂，可改善肽和蛋白质结构分析

自由基引发的肽测序（FRIPS）最近已被引入作为一种分析策略，通过对特定修饰肽段的碰撞活化，以可预测和有效的方式产生肽自由基离子离子。FRIPS基于开壳离子的单分子解离，其片段类似于通过电子俘获解离（ECD）或电子转移解离（ETD）获得的片段。在这篇综述文章中，我们描述了FRIPS的基本原理，并着重指出了FRIPS与化学交联/质谱（MS）的卓有成效的结合，是获得肽和蛋白质互补结构信息的极有前途的选择。FRIPS不仅可以产生交联肽段的详尽序列信息，而且可以定义所连接肽段的确切交联位点。迫切期望开发出更先进的FRIPS交联剂，从而将基于FRIPS的交联/ MS方法扩展到大型蛋白质装配体和蛋白质相互作用网络的研究中。