N-glycoproteomic profiling reveals structural and functional alterations in yellow primary preserved egg white under saline-alkali treatment

Abstract

The posttranslational N-glycosylation of food proteins is important to their structure and function. However, the N-glycoproteomics of yellow preserved egg white were rarely reported. This study explored the changes of N-glycoproteome in yellow preserved eggs white after salt and alkali treatment. A total of 213 N-glycosites were identified on 102 glycoproteins, revealing prevalent glycosylation motifs and multiple N-glycosites within proteins. Salt and alkali treatment significantly altered the glycosylation patterns, impacting major proteins differently. GO analysis indicated the roles of differentially expressed glycoproteins in responding to stimuli and biological regulation. KEGG analysis emphasized the importance of salivary secretion pathway in enzyme secretion and peptide generation. Protein domain analysis highlighted the downregulation of Serpin. Protein-protein interaction networks revealed Apolipoprotein B as central players. This study provides essential structural information on the glycosylation modifications of egg white proteins, contributing to our understanding of the mechanisms behind the functional properties of preserved eggs.

Keywords: Gene Ontology analysis; N-Glycoproteome; Saline-alkali treatment; Yellow preserved primary egg white.

Graphical abstract

Fig. 1

Characteristics of the identified N-glycopeptides. A. Number of spectrograms; B. Mass error distribution of identified N-glycopeptides; C. Percentage of N-glycopeptides possessing different glycosylation sites.

Fig. 2

N-glycosylation modification site motif.

Fig. 3

Expression pattern of quantifiable N-glycosites.

Fig. 4

A. Differential modification site/protein statistics; B. Distribution of differentially expressed proteins in GO secondary annotation statistics.

Fig. 5

Functional enrichment analysis of differentially expressed glycoproteins. A. KEGG pathway; B. Protein domain.

Fig. 6

The interaction between N-glycosylated modified proteins. The red circles represent upregulated N-glycoproteins, the yellow circles represent downregulated N-glycoproteins, and the width of the line represents the strength of the correlation. The blue circles represent N-glycoproteins in egg white of PEW and YPPEW samples. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)