GlycoFish: A Database of Zebrafish <i>N</i>-linked Glycoproteins Identified Using SPEG Method Coupled with LC/MS

Zebrafish (<i>Danio rerio</i>) is a model organism that is used to study the mechanisms and pathways of human disorders. Many dysfunctions in neurological, development, and neuromuscular systems are due to glycosylation deficiencies, but the glycoproteins involved in zebrafish embryonic development have not been established. In this study, a mass spectrometry-based glycoproteomic characterization of zebrafish embryos was performed to identify the <i>N</i>-linked glycoproteins and <i>N</i>-linked glycosylation sites. To increase the number of glycopeptides, proteins from zebrafish were digested with two different proteaseschymotrypsin and trypsininto peptides of different length. The <i>N</i>-glycosylated peptides of zebrafish were then captured by the solid-phase extraction of <i>N</i>-linked glycopeptides (SPEG) method and the peptides were identified with an LTQ OrbiTrap Velos mass spectrometer. From 265 unique glycopeptides, including 269 consensus NXT/S glycosites, we identified 169 different <i>N</i>-glycosylated proteins. The identified glycoproteins were highly abundant in proteins belonging to the transporter, cell adhesion, and ion channel/ion binding categories, which are important to embryonic, organ, and central nervous system development. This proteomics data will expand our knowledge about glycoproteins in zebrafish and may be used to elucidate the role that glycosylation plays in cellular processes and disease. The glycoprotein data are available through the GlycoFish database (http://betenbaugh.jhu.edu/GlycoFish) introduced in this paper.