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Xi Chen
Associate Professor

Email: chen@chem.ucdavis.edu
Phone:(530) 754-6037

B.S., Xiamen University, P. R. China, 1994.
Ph.D., Wayne State University, 2000.
Scientist, Neose Technologies, Inc. 2001-2003.
Appointed to faculty, UC Davis, 2003-present.
National Science Foundation CAREER Award, 2006.
Beckman Young Investigator Award, 2006.
CACPA Distinguished Junior Faculty Award, 2007.
SYNTHESIS, SYNLETT and SYNFACTS Thieme Chemistry Journal Award, 2008.

Group Page
Principal Research Interests
Carbohydrate Chemistry and Glycobiology, Chemical Biology, Bioorganic Chemistry: Chemoenzymatic synthesis of complex oligosaccharides, polysaccharides, and glycoconjugates; kinetics, enzyme mechanistic, X-ray crystal structure and mutagenesis studies of glycosyltransferases and other carbohydrate biosynthetic enzymes; carbohydrate-protein interactions; site-specific glycoconjugation; carbohydrates in cancer, bacterial and viral infection.
Representative Publications

Muthana, S.; Yu, H.; Huang, S.; *Chen, X. Chemoenzymatic synthesis of size-defined polysaccharides by sialyltransferase-catalyzed block transfer of oligosaccharides. J. Am. Chem. Soc. 2007, 129, 11918-11919.

Chokhawala, H. A.; Cao, H.; Yu, H.; *Chen, X. Enzymatic synthesis of fluorinated mechanistic probes for sialidases and sialyltransferases. J. Am. Chem. Soc. 2007, 129, 10630-10631.

Lewis, A. L.; Cao, H.; Patel, S. K.; Diaz, S.; Ryan, W.; Carlin, A. F.; Thon, V.; Lewis, W. G.; *Varki, A.; Chen, X.; Nizet, V. NeuA sialic acid O-acetylesterase activity modulates O-acetylation of capsular polysaccharides in Group B Streptococcus. J. Biol. Chem. 2007, 282, 27562-27571.

Li, Y.; Sun, M.; Huang, S.; Yu, H.; Chokhawala, H. A.; Thon, V.; *Chen, X. The Hd0053 gene of Haemophilus ducreyi encodes an ?2,3-sialyltransferase. Biochem. Biophys. Res. Commun. 2007, 361, 555-560.

Chokhawala, H.; Yu, H.; *Chen X. High-throughput substrate specificity studies of sialidases using chemoenzymatically synthesized sialoside libraries. ChemBioChem 2007, 8, 194-201.

Huang, S.; Yu, H.; *Chen, X. Disaccharides as sialic acid aldolase substrates: synthesis of disaccharides containing a sialic acid at the reducing end. Angew. Chem. Int. Ed. 2007, 5, 2249-2253.

Yu, H.; *Chen, X. Carbohydrate post-glycosylational modifications. Org. Biomol. Chem. (Emerging Area Article) Featured as cover picture, 2007, 5, 865-872.

Ni, L.; Chokhawala, H. A.; Cao, H.; Henning, R.; Ng, L.; Huang, S.; Yu, H.; *Chen, X.; *Fisher, A. J. Crystal structures of a Pasteurella multocida sialyltransferase complexes with acceptor and donor analogs reveal substrate binding sites and catalytic mechanism. Biochemistry 2007, 46, 6288-6298.

Yu, H.; Chokhawala, H. A.; Varki, A.; *Chen, X. Efficient chemoenzymatic synthesis of biotinylated human serum albumin-sialoglycoside conjugates containing O-acetylated sialic acids. Org. Biomol. Chem. 2007, 5, 2458-2463.

Yu, H.; Chokhawala, H.; Huang, S.; *Chen X. One-pot three-enzyme chemoenzymatic approach to the synthesis of sialosides containing natural and non-natural functionalities. Nature Protocols. 2006, 1, 2485-2492.

Yu, H.; *Chen X. Aldolase catalyzed synthesis of ?-D-Gal-(1?9)-D-KDN: A novel acceptor for sialyltransferases. Org. Lett. 2006, 8, 2393-2396.

Yu, H.; Huang, S.; Chokhawala, H.; Sun, M.; Zheng, H.; *Chen X. Highly efficient chemoenzymatic synthesis of naturally occurring and non-natural ?-2,6-linked sialosides: a P. damsela ?-2,6-sialyltransferase with extremely flexible donor substrate specificity. Angew. Chem. Int. Ed. 2006, 45, 3938-3944.

Ni, L.; Sun, M.; Yu, H.; Chokhawala, H.; *Chen, X.; *Fisher, A. J. Cytidine 5’-monophosphate (CMP)-induced structural changes in a multifunctional sialyltransferase from Pasteurella multocida. Biochemistry, 2006, 45, 2139-2148.

Yu, H.; Ryan, W.; Yu, H.; *Chen, X. Characterization of a bifunctional cytidine 5’-monophosphate N-acetylneuraminic acid synthetase cloned from Streptococcus agalactiae. Biotechnol. Lett. 2006, 28, 107-113.

Yu, H.; Chokhawala, H.; Karpel, R.; Yu, H.; Wu, B.; Zhang, J.; Zhang, Y.; Jia, Q.; *Chen, X. A multifunctional Pasteurella multocida sialyltransferase: a powerful tool for the synthesis of sialoside libraries. J. Am. Chem. Soc. 2005, 127, 17618-17619.

Yu, H.; Yu, H.; Karpel, R.; *Chen, X. Chemoenzymatic synthesis of CMP-sialic acid derivatives by a one-pot two-enzyme system: comparison of substrate flexibility of three microbial CMP-sialic acid synthetase. Bioorg. Med. Chem. 2004, 12, 6427-6435.