Investigation on the Synthesis of Shigella flexneri Specific Oligosaccharides Using Disaccharides as Potential Transglucosylase Acceptor Substrates.
Chemo-enzymatic strategies hold great potential for the development of stereo- and regioselective syntheses of structurally defined bioactive oligosaccharides. Herein, we illustrate the potential of the appropriate combination of a planned chemo-enzymatic pathway and an engineered biocatalyst for the multistep synthesis of an important decasaccharide for vaccine development. We report the stepwise investigation, which led to an efficient chemical conversion of allyl α-d-glucopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3)-2-deoxy-2-trichloroacetamido-β-d-glucopyranoside, the product of site-specific enzymatic α-d-glucosylation of a lightly protected non-natural disaccharide acceptor, into a pentasaccharide building block suitable for chain elongation at both ends. Successful differentiation between hydroxyl groups features the selective acylation of primary alcohols and acetalation of a cis-vicinal diol, followed by a controlled per-O-benzylation step. Moreover, we describe the successful use of the pentasaccharide intermediate in the [5 + 5] synthesis of an aminoethyl aglycon-equipped decasaccharide, corresponding to a dimer of the basic repeating unit from the O-specific polysaccharide of Shigella flexneri 2a, a major cause of bacillary dysentery. Four analogues of the disaccharide acceptor were synthesized and evaluated to reach a larger repertoire of O-glucosylation patterns encountered among S. flexneri type-specific polysaccharides. New insights on the potential and limitations of planned chemo-enzymatic pathways in oligosaccharide synthesis are provided.
Institut Pasteur , Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724, Paris Cedex 15 France.|CNRS UMR 3523, Institut Pasteur , 75015 Paris, France.
Stéphane
S
Salamone
Institut Pasteur , Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724, Paris Cedex 15 France.|CNRS UMR 3523, Institut Pasteur , 75015 Paris, France.
Catherine
C
Guerreiro
Université de Toulouse , INSA,UPS,INP; LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France.|CNRS, UMR5504 , F-31400 Toulouse, France.|INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés , F-31400 Toulouse, France.
Emmanuelle
E
Cambon
Institut Pasteur , Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724, Paris Cedex 15 France.|CNRS UMR 3523, Institut Pasteur , 75015 Paris, France.
Jason M
JM
Hargreaves
Université de Toulouse , INSA,UPS,INP; LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France.|CNRS, UMR5504 , F-31400 Toulouse, France.|INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés , F-31400 Toulouse, France.
Nathalie
N
Tarrat
Université de Toulouse , INSA,UPS,INP; LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France.|CNRS, UMR5504 , F-31400 Toulouse, France.|INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés , F-31400 Toulouse, France.
Magali
M
Remaud-Siméon
Université de Toulouse , INSA,UPS,INP; LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France.|CNRS, UMR5504 , F-31400 Toulouse, France.|INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés , F-31400 Toulouse, France.
Isabelle
I
André
Institut Pasteur , Unité de Chimie des Biomolécules, 28 rue du Dr Roux, 75724, Paris Cedex 15 France.|CNRS UMR 3523, Institut Pasteur , 75015 Paris, France.
Laurence A
LA
Mulard
D055162:Biocatalysis; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000737:chemistry*; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D012763:Shigella flexneri / Q000737:chemistry*
D004187:Disaccharides; D009844:Oligosaccharides; D005964:Glucosyltransferases