Identification of the Duck Egg White N‑Glycoproteome and Insight into the Course of Biological Evolution

Protein glycosylation is a ubiquitous
posttranslational modification
that modulates protein properties, thereby influencing bioactivities
within a system. Duck egg white (DEW) proteins exhibit diverse biological
properties compared with their chicken egg white (CEW) counterparts,
which might be related to glycosylation. N-Glycoproteome analysis
of DEW was conducted, and a total of 231 N-glycosites from 68 N-glycoproteins
were identified. Gene ontology analysis was used to elucidate the
biofunctions of DEW N-glycoproteins and compare them with those of
CEW, which showed that the differences mostly involved molecular functions
and biological processes. The biological functions of DEW N-glycoproteins
were illuminated through bioinformatics analysis and comparison with
CEW orthologues, which showed different allergenicities and antibacterial
abilities. These divergences might be initiated by specific alterations
in glycosylation, which can enhance the proteolysis resistance and
protein steric hindrance. These results provide new insights for discovering
the effects of N-glycosylation on biofunctions during the divergence
of homologous proteins.