A new sight to explore site-specific N-glycosylation in donkey colostrum milk fat globule membrane proteins with glycoproteomics analysis

Abstract

Donkey colostrum milk fat globule membrane (DCMFGM) proteins are involved in multiple biological functions. However, the effect of N-glycosylation on their physiological properties are unknown. The aim of this study was to map the DCMFGM protein site-specific N-glycosylation landscape using a label-free glycoproteomic approach. A total of 1,443 unique intact N-glycopeptides mapping to 453 unique N-glycosites on 336 N-glycoproteins were identified. The macro- and microheterogeneity of DCMFGM glycoproteins were explored at the N-glycosite level and the site-specific N-glycan level, respectively, and it was found that the N-glycosylation profiles of the DCMFGM proteins varied based on subcellular localisation and protein domain types. Our findings reveal the heterogeneity and functional diversity of N-glycosylation of DCMFGM proteins and provide theoretical support for the promotion of DCMFGM proteins as a functional food ingredient.