Comparative N-Glycoproteomic Investigation of Eggshell Cuticle and Mineralized Layer Proteins

Theeggshell cuticle layer (ECL) and eggshell mineralizedlayer(EML) contain amounts of glycoproteins and proteoglycans. However,there were few comprehensive reports about the effect of post-translationalmodifications on protein structure and function which requires investigation.Therefore, we used comparative N-glycoproteomicsto study glycoproteins in the ECL and EML. We identified a total of272 glycoproteins in this experiment and found that glycoproteinslocated in EML were more than that in ECL. Moreover, they showed distinctfunctional difference between both layers. As N-glycosylationof ovocleidin-17 and ovocleidin-116 in the EML affected eggshell mineralization,some glycoproteins located in ECL, like ovotransferrin and ovostatin-like,possessed antibacterial activity. The several regulated glycoproteinsin the EML may pertain to the regulation of mineralization, whileglycosylated proteins in the ECL may contribute to molecular adhesionand defense against microbial invasion. This study provides new insightsinto the eggshell matrix protein contents of the ECL and EML.

Automated summary

This study compared the glycoproteins between the eggshell cuticle layer (ECL) and eggshell mineralized layer (EML). It found that EML contained more glycoproteins and showed different functional characteristics compared to ECL. Glycoproteins in EML may be involved in mineralization regulation, while those in ECL may contribute to molecular adhesion and defense against microbial invasion.