The present invention provides engineered cells and methods for making high purity steviol glycosides, including RebM. In some aspects, the present invention provides host cells, such as bacterial cells (including but not limited to E. coli), that are engineered to overexpress and/or delete or inactivate one or more steviol glycoside transport proteins. The bacterial cells selectively export RebM, or other specific combination of steviol glycosides, out of the cell to increase productivity and reduce production costs associated with downstream purification. Non-target steviol glycosides are not transported to the extracellular medium in significant amounts.

The present invention relates, at least in part, to the production of steviol glycoside rebaudioside I through the use of variant UGT enzymes having activity to transfer a glucosyl group from UDP-glucose to rebaudioside A to produce rebaudioside I.

The invention relates to recombinant microorganisms and methods for producing steviol glycosides, glycosylated ent-kaurenol, and glycosylated ent-kaurenoic acid.

Provided is a method for preparing rebaudioside N using an enzymatic method, comprising using rebaudioside A or rebaudioside J as a substrate, and making the substrate, in the presence of a glycosyl donor, react under the catalysis of a UDP-glycosyl-transferase and/or a UDP-glycosyltransferase-containing recombinant cell to generate rebaudioside N.

The present disclosure relates to the production of steviol glycosides rebaudioside J and rebaudioside N through the use of rebaudioside A as a substrate and a biosynthetic pathway involving various 1,2 RhaT-rhamnosyltransferases.

The present invention relates, at least in part, to the production of steviol glycoside rebaudioside I through the use of variant UGT enzymes having activity to transfer a glucosyl group from UDP-glucose to rebaudioside A to produce rebaudioside I.

The present invention relates to the field of protein post-translational modification. More specifically, the present invention provides compositions and methods useful for identifying O-linked glycosylation sites in proteins. In one embodiment, the present invention provides a method for identifying O-linked glycosylation sites of Tn antigen in proteins comprising the steps of (a) digesting proteins present in a sample into peptides; (b) enriching for Tn-glycopeptides; (c) conjugating Tn-glycopeptides to solid phase; (d) labeling Tn using the glycosyltransferse enzyme C1GalT1 and a labeled uridine diphosphate galactose (UDP-Gal) substrate to produce labeled Tn-glycopeptides; (e) releasing the labeled Tn-glycopeptides from the solid-phase using an endopeptidase that cleaves peptides at the N-terminus of O-linked glycans at serine or threonine residues; and (f) mapping O-linked glycosylation sites of Tn antigen using liquid chromatography-mass spectrometry.

A bioconjugate of an E. coli glucosylated O4 antigen polysaccharide covalently linked to a carrier protein and compositions thereof are provided. Also provided are recombinant host cells for producing the bioconjugate, and methods of producing the bioconjugate using the recombinant host cells. The recombinant host cells contain a nucleic acid encoding a glucosyl transferase capable of modifying the E. coli O4 antigen with glucose branching to produce the glucosylated O4 antigen polysaccharide. Bioconjugates of an E. coli glucosylated O4 antigen polysaccharide described herein can be used alone or in combination with one or more additional E. coli O-antigen polysaccharides to induce antibodies against an E. coli glucosylated antigen, and to vaccinate a subject against extra-intestinal pathogenic E. coli (ExPEC).

Provided is a method for preparing Rehaudioside C using an enzymatic method, comprising using rubusoside or dulcoside A as a substrate, and making the substrate, in the presence of a glycosyl donor, react under the catalysis of UDP-glycosyltransferase-containing recombinant cell and/or UDP-glycosyltransferase prepared therefrom to generate Rebaudioside C.

Methods for making modified Fc regions of antibodies and antibody fragments, both human and humanized, and having enhanced stability and efficacy, are provided. Antibodies comprising Fc regions with core fucose residues removed, and attached to oligosaccharides comprising terminal sialyl residues, are provided. Antibodies comprising homogeneous glycosylation of Fc regions with specific oligosaccharides are provided. Fc regions conjugated with homogeneous glycoforms of monosaccharides and trisaccharides, are provided. Methods of preparing human antibodies with modified Fc using glycan engineering, are provided.