title: Trypanosoma brucei UDP-galactose-4'-epimerase in ternary complex with NAD+ and the substrate analogue UDP-4-deoxy-4-fluoro-alpha-D-galactose.
abstract: The structure of the NAD-dependent oxidoreductase UDP-galactose-4'-epimerase from Trypanosoma brucei in complex with cofactor and the substrate analogue UDP-4-deoxy-4-fluoro-alpha-D-galactose has been determined using diffraction data to 2.7 A resolution. Despite the high level of sequence and structure conservation between the trypanosomatid enzyme and those from humans, yeast and bacteria, the binding of the 4-fluoro-alpha-D-galactose moiety is distinct from previously reported structures. Of particular note is the observation that when bound to the T. brucei enzyme, the galactose moiety of this fluoro-derivative is rotated approximately 180 degrees with respect to the orientation of the hexose component of UDP-glucose when in complex with the human enzyme. The architecture of the catalytic centre is designed to effectively bind different orientations of the hexose, a finding that is consistent with a mechanism that requires the sugar to maintain a degree of flexibility within the active site.
authors.affiliation: Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland.
authors.forename: Magnus S
authors.initials: MS
authors.lastname: Alphey
authors.forename: Andrew
authors.initials: A
authors.lastname: Burton
authors.forename: Michael D
authors.initials: MD
authors.lastname: Urbaniak
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Boons
authors.forename: Michael A J
authors.initials: MA
authors.lastname: Ferguson
authors.forename: William N
authors.initials: WN
authors.lastname: Hunter
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D009243:NAD / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D013379:Substrate Specificity; D014346:Trypanosoma brucei brucei / Q000201:enzymology*; D014534:UDPglucose 4-Epimerase / Q000737:chemistry* / Q000378:metabolism; D014531:Uridine Diphosphate Galactose / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D009243:NAD; D014531:Uridine Diphosphate Galactose; D014534:UDPglucose 4-Epimerase