A chemoenzymatic approach for the synthesis of unnatural dissacharides containing D-galacto- or D-fucofuranosides
2005
Euzen, Ronan | Lopez, Gérald | Nugier-Chauvin, Caroline | Ferrières, Vincent | Plusquellec, Daniel | Rémond, Caroline | O Donohue, Michael
Unusual diglycosides composed of D-hexofuranosyl entities were prepared by a chemoenzymatic route using the alpha-L-arabinofuranosidase, AbfD3. The required, unprotected monosaccharidic donors were first prepared according to multi-step syntheses. Since one goal of this study was the investigation of donor -1 subsite in the active site of the enzyme, we focused on D-fucofuranosyl and 6-deoxy-6-fluoro-D-galactofuranosyl derivatives which present stereochemical similarities with L-arabinose series, but also structural variations on the side arm. These substrates were then used in AbfD3-catalysed hydrolyses to determine the parameters Km and kcat and in AbfD3-catalysed transglycosylation to evaluate their ability to serve as donor/acceptor. Four disaccharides were thus isolated and characterised, two resulting from beta-(1,2) connection along with two beta-(1,3)-regioisomers.
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