Affordable sialoglycans and associated reagents for expanded chemoenzymatic production

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Project Summary Sialoglycans are sialic acid-containing oligosaccharides that play important biological roles in human biology and pathology and are indispensable molecular probes for research related to bacterial and viral infection, cancer metastasis, immune regulation, etc. The multifaceted functions of sialoglycans in human milk are also being explored. Nevertheless, sialoglycan-related research and development of therapeutics and diagnostics have been hampered by the limited access to these structurally complex compounds as well as the high cost and special expertise needed for synthesizing and purifying these reagents. Among various synthetic strategies for producing sialoglycans, glycosyltransferase-based chemoenzymatic methods are attractive strategies. An efficient method for synthesizing structurally defined sialoglycans is one- pot multienzyme (OPME) chemoenzymatic strategy developed by Dr. Hai Yu and Dr. Xi Chen at UC Davis. Each OPME glycosylation reaction contains a glycosyltransferase and enzymes involved in generating the corresponding sugar nucleotide donor in situ from a simple monosaccharide. The OPME reactions allow the synthesis of target glycans containing the desired glycosidic linkage with high regio- and stereo-specificity. At the current stage, large-scale synthesis by the OPME systems is still limited by the scales and the yields of the enzymes produced. In addition, OPME reaction conditions can be improved to decrease the amounts of enzymes used for the synthesis. Product purification processes can also be streamlined using innovative strategies. To advance sialic acid-related research and therapeutic development, the goal of this proposed project is to develop reagents, enzymes, and methods that are ready for commercialization to allow low-cost access to sialoglycans of high demands and their underlying asialoglycans by the broad scientific community (both academic and industry) and to enable highly efficient production of diverse biologically important special sialoglycan targets by even nonspecialists. This will be achieved by the collaboration of the UC Davis team with IMCS which has expertise in high-yield enzyme production by fermentation, unique lysis technique, commercial infrastructure to manufacture, and product sale at affordable prices to the community.