title: Enzymatic synthesis of oligo-D-galactofuranosides and l-arabinofuranosides: from molecular dynamics to immunological assays.
abstract: D-Galactofuranosyl-containing conjugates are ubiquitous in many pathogenic microorganisms, but completely absent from mammals. As they may constitute interesting pharmacophores, recent works have been dedicated to their preparation. Besides well-reported chemical procedures, enzymatic approaches are still limited, mainly due to the lack of the corresponding biocatalysts. Based on the similarity between chemical structures, the arabinofuranosyl hydrolase Araf51 from Clostridium thermocellum was expected to recognize both the L-Araf motif and its D-Galf analogue. Molecular dynamics and STD-NMR were firstly used to confirm this hypothesis and increase our knowledge of the active site. Interestingly, this arabinofuranosidase was not only able to hydrolyze galactosyl derivatives, but was also really efficient in catalyzing oligomerisations using p-nitrophenyl furanosides as donors. The structures of the products obtained were determined using mass spectrometry and NMR. Amongst them, all the possible regioisomers of di-arabino and -galactofuranosides were synthesized, and the ratio of each regioisomer was easily tuned with respect to the reaction time. Especially, the galactofuranobioside displaying the biologically relevant sequence beta-D-Galf-(1,6)-beta-D-Galf was enzymatically prepared for the first time. All fractions going from di- to penta-arabino- and galactofuranosides were tested for their ability in eliciting the production of TNF-alpha. Interesting immunological properties were observed with arabinofuranosides as short as three sugar residues.
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France.
authors.forename: Ilona
authors.initials: I
authors.lastname: Chlubnová
authors.forename: Dominik
authors.initials: D
authors.lastname: Filipp
authors.forename: Vojtech
authors.initials: V
authors.lastname: Spiwok
authors.forename: Hana
authors.initials: H
authors.lastname: Dvoráková
authors.forename: Richard
authors.initials: R
authors.lastname: Daniellou
authors.forename: Caroline
authors.initials: C
authors.lastname: Nugier-Chauvin
authors.forename: Blanka
authors.initials: B
authors.lastname: Králová
authors.forename: Vincent
authors.initials: V
authors.lastname: Ferrières
mesh_terms: D000276:Adjuvants, Immunologic / Q000138:chemical synthesis* / Q000737:chemistry; D001089:Arabinose / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D055162:Biocatalysis; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005697:Galactosides / Q000138:chemical synthesis* / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data
chemical_list: D000276:Adjuvants, Immunologic; D005697:Galactosides; D001089:Arabinose; D006026:Glycoside Hydrolases