蛋白质组学中的基于二级质谱谱图定性流程的探究与改进

发布时间：2018-04-26 07:36

本文选题：蛋白质组学 + 定性流程　；参考：《华东师范大学》2017年硕士论文

【摘要】：随着质谱技术的进步,基于液相色谱串联质谱联用(LC-MS/MS)的分析技术,已经成为鸟枪法蛋白质组学研究中的最常用技术之一。在实验时,先将实验样本用相关蛋白酶水解成肽段,再将处理后的肽段混合物,经LC-MS/MS检测得到原始质谱数据。这些原始质谱数据,需要相关软件处理分析,才能知道原样本中的肽段、蛋白质是什么,这一步骤即质谱数据的定性。现行的定性方法多是基于蛋白序列理论库进行定性分析,如软件Mascot和X!Tandem等。但是这种方法有自己的局限性,比如该方法十分依赖于蛋白序列库、忽略理论谱图与实验谱图的差别、谱图鉴定率低等。针对上述问题,本文详细探究了基于二级谱图的定性流程(DDA采集模式下),对流程中的步骤逐一做了详细论述,以便了解现有定性方法中的关键步骤。在此基础上,对现有流程方法进行改进,提出了一套新的定性方法(SpectraMatch),该方法是基于已知的实验谱图库进行定性的,不同于蛋白序列搜索,这种方法让实验谱图之间直接进行比对,以此来进行定性分析。经验证,从肽段、蛋白和生物学意义等层面上,均能证明:本文提出的方法(SpectraMatch)与主流的软件(Mascot、X!Tandem、MSPepSearch 和 OMSSA)有较好的一致性,这证明了本文的探究和本文定性流程的可靠性和正确性。同时,因为本文方法可以轻松地更改参考谱图库,所以相比基于蛋白序列库方法有更强的灵活性。
[Abstract]:With the development of mass spectrometry, the analysis technology based on LC-MS / MS / MS has become one of the most common techniques in the research of birdshot proteomics. In the experiment, the sample was hydrolyzed into peptide segment with the related protease, then the mixture of the treated peptide segment was hydrolyzed to obtain the original mass spectrum data by LC-MS/MS detection. In order to know the peptide segment and the protein in the original sample, these raw mass spectrum data need to be processed and analyzed by relevant software. This step is the qualitative analysis of the mass spectrum data. The existing qualitative methods are based on the protein sequence theory library, such as software Mascot and XT Tandem. However, this method has its own limitations. For example, the method relies heavily on the protein sequence library, neglects the difference between theoretical and experimental spectra, and has a low spectral identification rate. In order to understand the key steps of the existing qualitative methods, this paper probes into the qualitative process based on the two-level spectrum diagram in DDA acquisition mode and discusses the steps in the process one by one. On this basis, the existing process methods are improved, and a new qualitative method is proposed, which is based on the known experimental spectrum map library, and is different from protein sequence search. This method allows the experimental spectra to be compared directly for qualitative analysis. It has been proved that the proposed method SpectraMatch has good consistency with the main software MascotX and MSPepSearch and OMSSA, which proves the reliability and correctness of the research and qualitative process of this paper. The results show that the method proposed in this paper is consistent with the software MascotX and MSPepSearch and OMSSA. it is proved that the proposed method is reliable and correct. At the same time, this method can easily change the reference map library, so it is more flexible than the protein sequence library method.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q51

【参考文献】