“自顶向下(top-down)”的蛋白质组学——蛋白质变体的规模化鉴定

高分辨率质谱技术的快速发展使得"自顶向下"的蛋白质组学(top-down proteomics)研究逐渐成熟起来.在完整蛋白质水平上研究蛋白质组可以提供更精准、更丰富的生物学信息,特别是对于蛋白质上发生了多种关联性的翻译后修饰的情况.另外,由于基因突变、RNA可变剪接和大量蛋白质翻译后修饰的存在,同一个基因往往最终会产生多个"蛋白质变体"(proteoform),而要准确地鉴定这些蛋白质变体,也离不开"自顶向下"的蛋白质组学.在蛋白质水平上的分离技术、质谱技术与生物信息学技术是完整蛋白质鉴定最关键的三项技术.高效的分离技术是实现规模化蛋白质变体鉴定的前提,有效的质谱碎裂是提供可靠鉴定的核心,而快速准确的质谱鉴定算法则是数据分析效率的保障.本文对这三项技术进行了详细总结,重点集中在生物信息学相关技术上,包括对完整蛋白质的质谱数据预处理、数据库搜索鉴定以及翻译后修饰定位等几个计算问题的讨论.

Top-down Proteomics: The Large-scale Proteoform Identification

With the rapid advancement of the high resolution mass spectrometry, top-down proteomics becomes the reality. Proteome research on the intact protein level will provide more precise and more abundant biological information. For example, it can detect the relationship between the multiple post-translational modifications. Due to the genetic mutation, alternative splicing of RNA and various post-translational modifications, one gene may produce multiple protein forms, now called 'proteoforms'. Top-down proteomics will help identify the proteoforms. The three pillar technologies in top-down proteomics are separation, mass spectrometry and bioinformatics from the point of view on the entire proteins. This paper reviews these technologies and puts more emphases on the bioinformatics related topics, including the mass spectral preprocessing, the database searching algorithms and the localization of post-translational modifications.