NMR Investigation of the Influence of Sulfate Groups at C‐2 and C‐4 on the Conformational Behavior of Fucoidan Fragments with Homo‐(1→3)‐Linked Backbone# |
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Authors: | Alexey A Grachev Alexey G Gerbst Nadezhda E Ustyuzhanina Alexander S Shashkov Anatolii I Usov |
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Institution: | Russian Academy of Sciences , N.D. Zelinsky Institute of Organic Chemistry , Moscow B‐334, Russia |
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Abstract: | The conformational behavior of 2‐O‐ and 4‐O‐sulfated derivatives of linear (1→3)‐linked di‐, tri‐, and tetrafucosides and 2,3‐branched tetrafucoside was studied by means of theoretical molecular modeling and experimental determination of trans‐glycosidic vicinal coupling constants 3JC,H. It was shown that O‐sulfation of (1→3)‐linked oligofucosides restricts their conformational flexibility and changes the conformational equilibrium if compared with the parent nonsulfated oligosaccharides. In the case of 2‐O‐sulfated oligofucosides, the conformations of O‐glycoside linkages depend on its location within the oligosaccharide chain and the chain length as well as on the presence of a 2,3‐branch, whereas the conformation of the (1→3)‐linkage in the presence of a 4‐O‐sulfate group only depends on the presence of a 2,3‐branch. |
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Keywords: | Fucoidan fragments Sulfate NMR Transglycosidic coupling constants NOE Conformational analysis |
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