title: An original chemoenzymatic route for the synthesis of beta-D-galactofuranosides using an alpha-L-arabinofuranosidase.
abstract: DGalactofuranose is a widespread component of cell wall polysaccharides in bacteria, protozoa and fungi, but is totally absent in mammals. Importantly, galactofuranose is a key constituent of major cell envelope polysaccharides in pathogenic mycobacteria. In this respect, galactofuranose-based glycoconjugates are interesting target molecules for drug design. O-Glycosidases and notably beta-D-galactofuranosidases could be useful tools for the chemoenzymatic synthesis of galactofuranosides, but to date no studies of this type have been reported. Here we report the use of a GH 51 alpha-l-arabinofuranosidase for the synthesis of beta-D-galactofuranosides. We have demonstrated that this enzyme can catalyse both the autocondensation of p-nitrophenyl-beta-D-galactofuranoside and the transgalactofuranosylation of benzyl alpha-D-xylopyranoside, forming p-nitrophenyl beta-D-galactofuranosyl-(1-->2)-beta-D-galactofuranoside and benzyl beta-D-galactofuranosyl-(1-->2)-alpha-D-xylopyranoside, respectively. Both reactions were very regiospecific and the reaction involving benzyl alpha-D-xylopyranoside afforded very high yields (74.8%) of the major product. To our knowledge, this demonstration of chemoenzymatic synthesis of galactofuranosides constitutes the very first use of an O-glycosidase for the synthesis of galactofuranosides.
authors.affiliation: Laboratoire de Technologie Enzymatique et Physico-chimie des Agroressources, UMR URCA/INRA FARE, 8 rue Gabriel Voisin, BP 316, F-51688 Reims, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Rémond
authors.forename: Richard
authors.initials: R
authors.lastname: Plantier-Royon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Aubry
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Donohue
mesh_terms: D001406:Bacillaceae / Q000201:enzymology; D002384:Catalysis; D004926:Escherichia coli / Q000235:genetics; D006026:Glycoside Hydrolases / Q000138:chemical synthesis* / Q000737:chemistry* / Q000235:genetics; D006031:Glycosylation; D006868:Hydrolysis; D007700:Kinetics; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011994:Recombinant Proteins / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C023112:exo-beta-D-galactofuranosidase; C019713:alpha-N-arabinofuranosidase