Identification and characterization of a prokaryotic Mannosyl-oligosaccharide Glucosidase (MOGS) and establishment of a functional complementation assay for MOGS activity.

Mannosyl-oligosaccharide Glucosidase (MOGS) initiates glycan trimming by specifically cleaving α-1,2-linked glucose residues on glycoproteins. MOGS is a key enzyme for proper N-glycosylation, and its defects are associated with rare disease MOGS related congenital disorders of glycosylation (MOGS-CDG). Although MOGS has been identified from most of eukaryotic organisms, its existence in prokaryotic remains unclear. In this study, a prokaryotic MOGS (pMOGS) was identified from Elizabethkingia meningoseptica FMS-007. During the process, a functional complementation assay was established by examining the N-glycans profile of a CWH41 (MOGS homologous gene) knockout strain of Saccharomyces cerevisiae. Using the assay system, the function of human MOGS and its disease related mutants were tested. This study extended our understandings of MOGS and our ability to approach MOGS-CDG.