Identification method of protein by MS/MS based on peak intensity identification ability

Abstract

The invention discloses a protein second-level mass spectrum identification method based on peak intensity recognition capability. The method comprises the following steps: firstly, virtualizing enzymatically hydrolyzed protein database sequence, establishing a peptide fragment database and a peptide fragment database index for peptide fragments subjected to enzymatic hydrolysis according to the mass number of the peptide fragments; then, finding out candidate peptide fragments conforming to the requirement from the established peptide fragment database according to the mass number of parent ions without charges in a to-be-analyzed experiment spectrum; then removing an isotopic peak and selecting an effective peak from the to-be-analyzed experiment spectrum so as to generate a theory spectrum of the candidate peptide fragments conforming to the requirement, counting peak intensity information of different ions, calculating the peak intensity recognition capability of different types of ions at different intervals, marking each candidate peptide fragment based on the peak intensity recognition capability, and selecting the peptide fragment with the highest mark as the authentication result of the experiment spectrum; and finally, performing quality control on the authentication result. The number of valid mass spectra and the number of valid protein peptide fragments, which are authenticated by the method, are both higher than those obtained by an existing algorithm; peaks can be selected dynamically; the running speed is high.

Description

technical field [0001] The invention relates to the field of protein secondary mass spectrometry identification, in particular to a protein secondary mass spectrometry identification method based on peak intensity recognition ability. Background technique [0002] Biomass spectrometry, which is composed of multidimensional chromatography and mass spectrometry, is widely used in proteomics, especially the emergence of two soft ionization technologies, matrix-assisted laser desorption (MALDI) and electrospray ionization (ESI), which make biological Mass spectrometry can introduce fewer impurities and maintain the integrity of peptide molecules, which opens a new page for the study of protein mass information and structural information. Mass spectrometry data processing technology plays an important role in proteome research, and its main task is to infer the protein composition of samples from data with complex noise or missing information. Database search is the main method ...

AI Technical Summary

Problems solved by technology

In the current scoring model of protein MS / MS identification algorithm, the scoring content can be roughly divided into the following three aspects: (1) peak matching and mismatching, (2) peak continuous matching, (3) peak intensity matching; among them (1) ), (2) have been widely considered in algorithm design, but (3) is rarely introduced into the algorithm

The recently published protein secondary mass spectrometry identification algorithm ProVerB well introduces (1), (2) and (3) into the algorithm construction, and the identification results are significantly better than Mascot and Sequest, providing a basis for the study of protein structure information and functional domains. However, based on the current protein identification algorithm, the scoring model does not involve the important characteristic information of intensity identification ability.

Images