Crystal structure of the retaining galactosyltransferase LgtC from Neisseria meningitidis in complex with donor and acceptor sugar analogs

• Published in: Nature structural biology Vol. 8; no. 2; pp. 166 - 175
• Main Authors: Strynadka, Natalie C.J, Persson, Karina, Ly, Hoa D, Dieckelmann, Manuela, Wakarchuk, Warren W, Withers, Stephen G
• Format: Journal Article
• Language: English
• Published: United States 01-02-2001
• Subjects: Amino Acid Sequence; Bacterial Proteins; Binding Sites; Carbohydrate Metabolism; Carbohydrates - chemistry; Catalysis; Crystallography, X-Ray; Drug Design; Galactosyltransferases - antagonists & inhibitors; Galactosyltransferases - chemistry; Galactosyltransferases - genetics; Galactosyltransferases - metabolism; Glycosyltransferases - antagonists & inhibitors; Glycosyltransferases - chemistry; Glycosyltransferases - genetics; Glycosyltransferases - metabolism; Hydrogen Bonding; Kinetics; Lactose - analogs & derivatives; Lactose - metabolism; LgtC protein; Manganese - metabolism; Models, Molecular; Molecular Sequence Data; Mutation - genetics; Neisseria meningitidis; Neisseria meningitidis - enzymology; Neisseria meningitidis - genetics; Protein Structure, Secondary; Sequence Alignment; Uridine Diphosphate Galactose - analogs & derivatives; Uridine Diphosphate Galactose - metabolism
• ISSN: 1072-8368; 2331-365X
• DOI: 10.1038/84168

Many bacterial pathogens express lipooligosaccharides that mimic human cell surface glycoconjugates, enabling them to attach to host receptors and to evade the immune response. In Neisseria meningitidis, the galactosyltransferase LgtC catalyzes a key step in the biosynthesis of lipooligosaccharide structure by transferring alpha-d-galactose from UDP-galactose to a terminal lactose. The product retains the configuration of the donor sugar glycosidic bond; LgtC is thus a retaining glycosyltranferase. We report the 2 A crystal structures of the complex of LgtC with manganese and UDP 2-deoxy-2-fluoro-galactose (a donor sugar analog) in the presence and absence of the acceptor sugar analog 4'-deoxylactose. The structures, together with results from site-directed mutagenesis and kinetic analysis, give valuable insights into the unique catalytic mechanism and, as the first structure of a glycosyltransferase in complex with both the donor and acceptor sugars, provide a starting point for inhibitor design.