Structural characterization of zebrafish Ngly2, an ovary-enriched acid PNGase required for egg free glycan production

Peptide:N-glycanase (PNGase) is a deglycosylating enzyme acting on asparagine(N)-linked glycans on glycoproteins. It is well established that fish possesses two PNGases with distinct properties. One is a cytosolic PNGase (NGLY1 in human), active at neutral pH and widely conserved among eukaryotes. The other is called acid PNGase and found in fish embryos; it is active at acidic pH and is believed to be of lysosomal origin. The gene encoding the acid PNGase has not been identified in animals, and its evolutionary distribution has remained unknown. In this study, we identified the gene encoding the acid PNGase, which we named Ngly2, in zebrafish (Danio rerio).