Oligosaccharides solution conformations

Robert J. Woods, The Application of Molecular Modeling Techniques to the Determination of Oligosaccharide Solution Conformations. 

Woods RJ. The application of molecular modeling techniques to the determination of oligosaccharide solution conformations. In Lipkowitz KB, Boyd DB, eds. Reviews in Computational Chemistry. Vol. 9. New York VCH, 1996 129-165. 

R. J. Woods, The Application of Molecular Modeling Techniques to the Determination of Oligosaccharide Solution Conformations, Reviews in Computational Chemistry, Vol. 9, K. B. Lipkowitz and D. B. Boyd, Eds., Wiley, New York, 1996, p. 129. 

Fig. 3—Possible solution conformers of oligosaccharide sequences related to the Le and Leb antigens (Lea,Lex, sialyl Le", sialyl Lex, ALeb, ALey). As described in the text, oligosaccharides in solution sample 3D space in local energy-minima wells, so that the conformations shown are approximate only. The models stand only to show the stereochemical hindrance to movement in these branched oligosaccharides. The molecules are shown without the anomeric hydroxyl group. 

Molecular Mechanics NMR Pseudoenergy Protocol To Determine Solution Conformation of Complex Oligosaccharides... 

There is a variety of methods for the determination of the structure of oligosaccharides. Different techniques are available for the determination of solution conformations and crystal structures respectively. The following section will deal with the most frequently used techniques. 

NMR spectroscopy has developed during the last few years into a very powerful method to establish both the conformation of an oligosaccharide in solution and in the crystalline state. The solution conformation of a saccharide can be determined generally by the combination of 13C-NMR and H-NMR techniques. 2-d methods became available in the last few years and are prerequisites for the elucidation of the three dimensional structure of an oligosaccharide [7]. Both NOE measurements [21] as well as traditional determination of coupling constants and chemical shifts are important tools for the determination of preferred conformations. 2-dimensional methods have greatly improved the accessibility of these parameters from complex molecules. 

The specific correlations of functional groups with the chemical shifts of carbon and associated protons are always important tools for structure elucidation of simple sugars as well as complex oligosaccharides. The conformational behavior [65,66] of a particular disaccharide and oligosaccharide in solution is determined not only by intramolecular interactions but also by potential interactions that exist between the oligosaccharide and its environment. In particular, the nature of the solvent or more generally the environment in which the compound finds itself, can profoundly affect its geometry. Two such important factors, namely the fully solvated state (i. e. the molecule free in solution) and the molecule solvated by a macromolecular receptor (i. e. the molecule bound to the active site of the protein) contribute to the preferred conformation. 

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