N-糖肽的规模化质谱解析方法进展

蛋白质糖基化修饰的鉴定是蛋白质翻译后修饰分析中最具挑战性的任务之一,近几年尤其受到关注.快速发展的质谱技术为规模化的蛋白质糖基化修饰研究提供了有效的手段.与其他基于质谱技术的翻译后修饰鉴定相比,糖基化鉴定的难点在于糖链是大分子而且存在微观不均一性,另外糖链本身可以在串联质谱中碎裂且与肽段的碎裂规律不同,导致蛋白质组学的质谱解析方法和软件难以完整地鉴定肽段序列和糖链结构.完整N-糖肽的鉴定是糖基化分析的热点内容之一,针对N-糖肽的鉴定,近年来,人们开发了多种多样的质谱解析方法,其中包括用N-糖酰胺酶切除糖链后鉴定N-糖基化位点的方法、基于电子转运裂解的糖肽肽段鉴定、基于高能碰撞裂解与电子转运裂解联用或碰撞诱导裂解与三级谱联用的完整N-糖肽鉴定等等.本文对这些质谱解析方法进行了整理和综述,简要指出了目前完整糖肽鉴定软件存在的一些不足,展望了未来的发展方向.

Trends in Mass Spectrometry-Based Large-scale N-Glycopeptides Analysis

Identification of post-translational modifications is one of the most challenging tasks in proteomics, and the analysis of glycosylation is a very important yet difficult one among all post-translational modifications, which has attracted more and more attention in recent years. Mass spectrometry provides an effective way for the high-throughput analysis of glycosylation. Comparing with most of the other post-translational modifications, glycans are large and hetorogeneous, and glycans themselves could be fragmented in tandem mass spectrometry, in particular, the fragmentation patterns of glycans are quite different from those of peptides, resulting in difficulties in simultaneously identifying glycans and peptides of intact glycopeptides using proteomic analytical methods and software tools. The identification of intact N-glycopeptides is a hot spot in glycosylation research, for which various mass spectrometry-based analytical methods have been developed in recent years, including deglycosylation for the identification of N-glycosylated sites, electron transfer dissociation for the identification of peptide backbones, the combination of higher energy collisional dissociation and electron transfer dissociation or the combination of collision-induced dissociation and MS3 for complete identification of intact N-glycopeptides. In this article, we reviewed these analytical methods, and briefly pointed out the deficiencies of existing software tools, and suggested some future work.