The present invention provides for recombinant Endo-S mutants that exhibit reduced hydrolysis activity and increased transglycosylation activity for the synthesis of glycoproteins wherein a desired sialylated oxazoline or synthetic oligosaccharide oxazoline is added to a core fucosylated or nonfucosylated GlcNAc-protein acceptor. Such recombinant Endo-S mutants are useful for efficient glycosylation remodeling of IgG1-Fc domain to provide different antibody glycoforms carrying structurally well-defined Fc N-glycans.

The present invention provides for the use of recombinant Endo-S2 mutants (named Endo-S2 glycosynthases) that exhibit reduced hydrolysis activity and increased transglycosylation activity for the synthesis of glycoproteins wherein a desired sugar chain is added to a fucosylated or nonfucosylated GlcNAc-IgG acceptor. As such, the present invention allows for the synthesis and remodeling of therapeutic antibodies thereby providing for certain biological activities, such as, prolonged half-life time in vivo, less immunogenicity, enhanced in vivo activity, increased targeting ability, and/or ability to deliver a therapeutic agent.

The present disclosure provides a one-pot chemoenzymatic method for site-specific modification and conjugation of antibodies at their Fc glycan site to produce structurally well-defined antibody conjugates carrying defined drugs and other entities. The method is enabled by the discovery that certain endoglycosidases have the ability to both deglycosylate an antibody and to recognize selectively modified small disaccharide oxazolines for transglycosylation on antibodies without hydrolysis of the resulting products.

The present application relates to the field of glyco-engineering, more specifically to glyco-engineering of Fc-containing molecules, such as antibodies. It is shown herein that Fc-containing molecules with a specific glycosylation pattern have a considerably longer circulating half-life in vivo, without having an altered binding affinity for their respective antigen. This has therapeutic implications in reducing the frequency with which these molecules need to be administered, without affecting therapeutic efficacy. Also, cells are provided that can produce the Fc molecules with the desired glycosylation pattern.

The present invention provides for a one-pot enzymatic approach which does not require removal of the enzyme and purification of the intermediate after deglycosylation step, and the Endo-S treatment is able to do both deglycosylation and transglycosylation. The one-pot strategy of the present invention enables chemoenzymatic synthesis of an azido-tagged N-glycoform of monocloncal antibodies which could be further modified through orthogonal chemical ligation for various applications.

The inventions described herein relate generally to compositions comprising bioactive proteins including, but not limited to, enzymes and antimicrobial proteins. Such bioactive protein compositions may be present alone or in a mammalian milk or soy-based nutritional product to increase colonization of desired commensal organisms, reduce potential pathogens, restore microbiome function, and/or otherwise improve health in a mammal consuming same.

The present invention relates to materials and methods for engineering, expression and high-level production of cost effective, safe and functional active recombinant truncated human Angiotensin-converting enzyme 2 (ACE2) in plants using transient expression system. In particular, the present invention relates to the production of glycosylated and non-glycosylated forms of ACE2 polypeptide in Nicotiana benthamiana (N. benthamiana) plant. The cost effective, safe and functional active plant produced recombinant ACE2 polypeptides can be used as a potential therapeutic target in COVID-19 patients to block or slow down the virus entering, spread of the virus and protect the lung from injury, also recombinant ACE2 enzymes are used as potential drugs to treat patients by controlling blood pressure.

The present application relates to the field of glyco-engineering and, more specifically, to eukaryotic cells wherein both an endoglucosaminidase is present and made deficient in UDP-galactose 4-epimerase (GalE). Typically, a glycoprotein is also present in the cells. These cells can be used to deglycosylate or partly deglycosylate the (exogenous) glycoprotein, in particular, without the need for adding an extra enzyme. Methods are also provided for the application of these cells in protein production.

The invention concerns fusion proteins, wherein two endoglycosidases are fused, possibly via a linker. The fusion enzymes according to the invention have structure (1): EndoX-(L).sub.p-EndoY (1), wherein EndoX is an endoglycosidase, EndoY is an endoglycosidase distinct from EndoX, L is a linker and p is 0 or 1. Such fusion enzymes capable of trimming glycoproteins comprising at least two distinct glycoforms in a single step. The invention further concerns the use of the fusion enzyme according to the invention for trimming glycoproteins. In another aspect, the invention relates to the process of production of the fusion enzyme. In a further aspect, the inventions concerns a process for trimming glycoproteins, comprising trimming the glycoprotein with a fusion enzyme according to the invention, to obtain a trimmed glycoprotein.

Provided herein are deglycosylating enzymes that remove a broad range of N-glycans from N-glycosylated proteins. Further provided are methods of recombinantly producing and expressing the deglycosylating enzymes. The presently described deglycosylating enzymes can be used to produce free glycans for characterization, and for prebiotic and immunostimulatory uses. In addition, the presently described deglycosylating enzymes can be used to produce deglycosylated proteins for characterization, to improve digestion, and to reduce immunogenicity.