Abstract: The present disclosure provides mutated PglB oligosaccharyltransferase enzymes that have the ability to efficiently catalyze the transfer of a saccharide from a lipid carrier to an asparagine reissue in a glycosylation motif on a protein. Also provided are polynucleotides encoding the mutated PglB oligosaccharyltransferase enzymes, host cells capable of expressing the engineered PglB oligosaccharyltransferase enzymes, and methods of using the engineered PglB oligosaccharyltransferase enzymes to make N-glycosylated proteins. Also provided are N-glycosylated proteins that are made using the engineered PglB oligosaccharyltransferase enzymes.