Methods of Glycosylation and Bioconjugation

Background:
The National Cancer Institute's Structural Glycobiology Laboratory is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, and/or commercialize methods of glycosylation and bioconjugation that can be used to regulate cellular recognition and interaction.

Technology:
Eukaryotic cells express several classes of oligosaccharides attached to proteins or lipids. Animal glycans can be N-linked via B-GlcNAc to Asn (N-glycans), O-linked via -GalNAc to Ser/Thr (O-glycans), or can connect the carboxyl end of a protein to a phosphatidylinositol unit (GPI-anchors) via a common core glycan structure. Beta (1,4)-galactosyltransferase I catalyzes the transfer of galactose from the donor, UDP-galactose, to an acceptor, N-acetylglucosamine, to form a galactose-beta (1,4)-N-acetylglucosamine bond, and allows galactose to be linked to an N-acetylglucosamine that may itself be linked to a variety of other molecules. Examples of these molecules include other sugars and proteins. The reaction can be used to make many types of molecules having great biological significance. For example, galactose-beta (1,4)-N-acetylglucosamine linkages are important for many recognition events that control how cells interact with each other in the body, and how cells interact with pathogens. In addition, numerous other linkages of this type are also very important for cellular recognition and binding events as well as cellular interactions with pathogens, such as viruses. Therefore, methods to synthesize these types of bonds have many applications in research and medicine to develop pharmaceutical agents and improved vaccines that can be used to treat disease.

The invention provides in vitro folding method for a polypeptidyl-a-N-acetylgalactosaminyltransferase (pp-GalNAc-T) that transfers GalNAc to Ser/Thr residue on a protein. The application claims that this in vitro-folded recombinant ppGalNAc-T enzyme transfers modified sugar with a chemical handle to a specific site in the designed C-terminal polypeptide tag fused to a protein.

Further R&D Needed:

• Development of a targeted drug delivery system.
• Attachment of fluoroprobes or imaging agents to proteins

R&D Status:
Enzymes have been synthesized and characterization studies have been performed.

IP Status:
U.S. Provisional Application No. 60/930,294

Value Proposition:

• Methods for engineering a glycoprotein from a biological substrate, and methods for glycosylating a biological substrate for use in glycoconjugation;
• Enzymes and methods that can be used to promote the chemical linkage of biologically important molecules that have previously been difficult to link;
• Diagnostics and therapeutics utilizing these methods.

Contact Information:
John D. Hewes, Ph.D., NCI Technology Transfer Center
Phone: 301-435-3121
E-mail: Hewesj@mail.nih.gov

Reference:  #598 JH

Posted 12/26/2007