We are working with Professor Andrew Fisher on structure and mutagenesis studies of glycosyltransferases and other carbohydrate biosynthetic enzymes. The purpose of this project is not only to understand the structure-function relationship of these carbohydrate biosynthetic enzymes, but also to generate mutants that can serve as better catalysts for our synthesis. Based on the crystal structures, we have successfully generated sialyltransferase mutants with altered linkage specificity and improved sialyltransferase activity by structure-guided saturated mutagenesis. Furthermore, we have developed a set of probes that can be used to identify sialidases with glycosidic linkage specificity in a high-throughput fashion.