Analysis of mutation‐originated gain‐of‐glycosylation using mass spectrometry‐based N‐glycoproteomics

Abstract

RationaleA general N‐glycoproteomics analysis pipeline has been established for characterization of mutation‐related gain‐of‐glycosylation (GoG) at intact N‐glycopeptide molecular level, generating comprehensive site and structure information of N‐glycosylation.MethodsThis study focused on mutation‐originated GoG using a mass spectrometry‐based N‐glycoproteomics analysis workflow. In brief, GoG intact N‐glycopeptide databases were built, consisting of 2701 proteins (potential GoG N‐glycosites and amino acids derived from MUTAGEN, VARIANT and VAR_SEQ in UniProt) and 6709 human N‐glycans (≤50 sequence isomers per monosaccharide composition). We employed the site‐ and structure‐specific N‐glycoproteomics workflow utilizing intact N‐glycopeptides search engine GPSeeker to identify GoG intact N‐glycopeptides from parental breast cancer stem cells (MCF‐7 CSCs) and adriamycin‐resistant breast cancer stem cells (MCF‐7/ADR CSCs).ResultsWith the criteria of spectrum‐level false discovery rate control of ≤1%, we identified 87 and 94 GoG intact N‐glycopeptides corresponding to 37 and 35 intact N‐glycoproteins from MCF‐7 CSCs and MCF‐7/ADR CSCs, respectively. Micro‐heterogeneity and macro‐heterogeneity of N‐glycosylation from GoG intact N‐glycoproteins with VAR_SEQ and VARIANT were found in both MCF‐7 CSCs and MCF‐7/ADR CSCs systems.ConclusionsThe integration of site‐ and structure‐specific N‐glycoproteomics approach, conjugating with GoG characterization, provides a universal workflow for revealing comprehensive N‐glycosite and N‐glycan structure information of GoG. The analysis of mutation‐originated GoG can be extended to GoG characterization of other N‐glycoproteome systems including complex clinical tissues and body fluids.