基于质谱的蛋白质O-糖基化分析

Mass Spectrometry Based Analysis of Protein O-glycosylation

蛋白质的O-糖基化是一种重要的蛋白质翻译后修饰,它和N-糖基化一样是蛋白质糖基化修饰的主要形式。蛋白质的O-糖基化对蛋白质的结构功能有重要的影响,因此分析蛋白质的O-糖基化具有重要的生物学意义。蛋白质O-糖基化分析包含4个方面的内容:(1)鉴定O-糖基化蛋白质的种类;(2)鉴定糖基化位点;(3)鉴定糖链结构;(4)糖链的定量分析。由于缺少保守的O-糖基化氨基酸特征序列,缺乏通用的糖苷酶以及O-糖链结构的复杂性等原因,基于质谱的蛋白质O-糖基化的分析目前仍处于方法开发阶段。本文主要介绍基于质谱的O-糖基化蛋白质的分析方法学在近期取得的一些进展,包括以下4个方面:O-糖蛋白/多肽的富集、O-糖链的解离、O-糖链的结构分析及O-糖基化定量分析。

O-glycosylation is an important post translational modification of proteins.It is the main type of protein glycosylation as well as N-glycosylation.Because of its significant roles in modulating the function and structure of proteins,it is necessary to study protein O-glycosylation in biomedicine research.The main tasks of protein O-glycosylation analysis are：（1） identification of O-glycosylated proteins,（2） location of O-glycosylation site on proteins,（3） O-glycan structure interpretation and（4）quantitative analysis.Mass spectrometry（MS） has become the key technology for the analysis of protein O-glycosylation.However,the analysis of O-glycosylation is a challenge： there is no consensus sequence of O-glycosylation and no universal cleavage enzyme,and the O-glycans are very complicated.Besides the invention of new instruments like LTQ Velos,many novel methods have been reported recently to conquer this challenge.In this review we try to cover these improvements for analysis of protein O-glycosylation,including four aspects： enrichment of O-glycoproteins /peptides,dissociation of O-glycan from proteins,O-glycan structure identification and quantitative analysis.