NDP-sugar glycosyltransferases are critical for the biosynthesis of all complex carbohydrates and glycoconjugates. This large and diverse class of enzymes catalyzes the transfer of saccharide units onto the target compounds to create a diverse set of macromolecules in plants, animals, and bacteria: glycolipids, lipopolysaccharides, the glycan structures in plants, glycoproteins, and glycosylated natural products of biomedical importance like antibiotics, hormones, antitumor agents, and cardiac glycosides. Initially, we intend to determine the X-ray crystal structures of 3 subfamilies of the family 1 NDP-sugar glycosyltransferases (GTFs): GTFs involved in the biosynthesis of vancomycin group antibiotics, GTFs which create sterol glucosides, and two GTFs involved in the glycosylation of diacylglycerol. Our goals are to elucidate (1) the physical basis for the recognition of NDP-sugars, (2) the physical basis for the recognition of the aglycone acceptors, and (3) the mechanism of glycosyltransfer. Understanding the structural diversity of these enzymes will enhance our understanding of glycobiology, particularly regarding the biosynthesis of glycolipids, glycosteroids, and antibiotics. A better understanding of the glycosylation of secondary metabolites will also open up new avenues for antibiotic design against pathogenic organisms and the design of other biomedically relevant compounds (e.g., cardiac glycosides or antitumor agents). Family 1 NDP-sugar glycosyltransferases show significant conservation of functionality among homologous enzymes across species as well as between analogous enzymes within a species, despite very low levels of amino acid sequence conservation (often <25% identity) in many cases. Recent research has also detected distinct elements of structural homology that are conserved between all members of this functional class. With comparative protein sequence analysis, a structural database of the family 1 enzyme could allow the modeling of any structurally unknown protein within this family. Moreover, the relatively simple bi-domain design of family 1 NDP-sugar glycosyltransferases raises the possibility of designing chimeric enzymes with novel functionalities. Mixing hybrid enzyme design with combinatorial biosynthesis could provide practical ways to produce new glycoconjugates of biomedical importance.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM065501-02
Application #
6795593
Study Section
Biophysical Chemistry Study Section (BBCB)
Program Officer
Marino, Pamela
Project Start
2003-09-01
Project End
2007-08-31
Budget Start
2004-09-01
Budget End
2005-08-31
Support Year
2
Fiscal Year
2004
Total Cost
$261,625
Indirect Cost
Name
Michigan State University
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
193247145
City
East Lansing
State
MI
Country
United States
Zip Code
48824
Zheng, Yi; Anderson, Spencer; Zhang, Yanfeng et al. (2011) The structure of sucrose synthase-1 from Arabidopsis thaliana and its functional implications. J Biol Chem 286:36108-18
King, Jerry D; Poon, Karen K H; Webb, Nicole A et al. (2009) The structural basis for catalytic function of GMD and RMD, two closely related enzymes from the GDP-D-rhamnose biosynthesis pathway. FEBS J 276:2686-2700
Powers, Rachel A; Rife, Christopher L; Schilmiller, Anthony L et al. (2006) Structure determination and analysis of acyl-CoA oxidase (ACX1) from tomato. Acta Crystallogr D Biol Crystallogr 62:683-6
Mulichak, Anne M; Lu, Wei; Losey, Heather C et al. (2004) Crystal structure of vancosaminyltransferase GtfD from the vancomycin biosynthetic pathway: interactions with acceptor and nucleotide ligands. Biochemistry 43:5170-80