A method for the identification of complex cross-linked peptides based on mass spectrometry

Abstract

The invention relates to a method for identifying complex cross-linked peptides based on mass spectrometry, which belongs to the technical field of biological analysis. The method of the present invention first theoretically digests the protein in the protein library and establishes a peptide index; then assumes the cross-linking site on each peptide and establishes an ion index; then performs an ion complementarity assumption on the spectrum and The ion index was used for peptide spectrum matching, and finally the final result was obtained after rough scoring, fine scoring and re-scoring. The method can directly realize the peptide spectrum matching between the spectrogram and all cross-linked peptides that meet the conditions, and the correct result peptides of the spectrogram are basically distributed in the top positions, and only need to be searched in a small search space. A fine score will recall the correct result.

Description

technical field [0001] The invention relates to a method for identifying complex cross-linked peptides based on mass spectrometry, which belongs to the technical field of biological analysis. Background technique [0002] Cross-linking proteomics aims to elucidate the structural characteristics of protein networks in cells, understand the mechanism of life at the molecular level, and ultimately be used for drug design. Cross-linking mass spectrometry has the characteristics of high throughput and high sensitivity, and can achieve large-scale acquisition of protein cross-linking in complex samples. Among them, the identification of cross-linked peptides is the key to obtain protein cross-linking information. Cross-linked peptides include three basic forms: mono-link, loop-link, and cross-link, also known as simple cross-linked forms. However, in the actual process, affected by the uneven distribution of enzyme cleavage sites and cross-linking sites, the obtained cross-linke...

AI Technical Summary

Problems solved by technology

At present, many methods are available for the identification of simple cross-linked peptides in mass spectrometry data, but there is little research on the identification of complex cross-linked peptides

Because there are multiple cross-links in complex cross-linked peptides, the fragmentation rules and fragment ions are not exactly the same as those of simple cross-linked peptides, so the identification method of simple cross-linked peptides cannot be used for the identification of complex cross-linked peptides. Identification

Due to the introduction of multiple cross-links, even if the peptide bonds between the cross-link sites in the peptide are broken, there is no difference in the mass of the fragment ions obtained, and they do not help in the peptide spectrum matching process.

These fragment ions, if normally generated and used for peptide spectrum matching, will lead to erroneous identification results.

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