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Improved In-gel Reductive β-Elimination for Comprehensive O-linked and Sulfo-glycomics by Mass Spectrometry
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Hydroxymethyl rotamer populations in disaccharides.
Alfredo Roën1, Juan I Padrón, Jesús T Vázquez
1Instituto Universitario de Bio-Orgánica Antonio González, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez 2, 38206 La Laguna, Tenerife, Spain.
The Journal of Organic Chemistry
|June 7, 2003
Summary
This study synthesized and analyzed methyl glucopyranoside disaccharides, revealing how glycosidic linkage type and solvent affect hydroxymethyl group rotation. These findings clarify carbohydrate structure-function relationships.
Area of Science:
- Carbohydrate Chemistry
- Structural Biology
- Spectroscopy
Background:
- Disaccharides are fundamental building blocks in biological systems.
- Understanding the conformational preferences of disaccharides is crucial for elucidating their structure-activity relationships.
- Hydroxymethyl group rotation significantly influences the overall conformation and properties of carbohydrates.
Purpose of the Study:
- To synthesize and characterize sixteen methyl glucopyranoside disaccharides with varying glycosidic linkages (1-->2, 1-->3, 1-->4, 1-->6).
- To investigate the influence of glycosidic linkage type, solvent, and substituents on hydroxymethyl rotational populations.
- To elucidate the roles of nonbonded interactions, exo-anomeric effect, and hydrogen bonding in determining disaccharide conformation.
Main Methods:
- Synthesis of sixteen methyl glucopyranoside disaccharides.
- Analysis using Circular Dichroism (CD) and Nuclear Magnetic Resonance (NMR) spectroscopy.
- Conformational analysis in three different solvent systems.
Main Results:
- Observed correlations between hydroxymethyl rotational populations, anomeric configuration, substituents, and solvent.
- Demonstrated that (1-->6)-linked disaccharides are primarily influenced by the exo-anomeric effect.
- Showed that (1-->2)-linked disaccharides depend strongly on anomeric configuration, while (1-->3)- and (1-->4)-linked disaccharides are influenced by substituents and solvent.
Conclusions:
- Hydroxymethyl rotational preferences are dependent on the specific glycosidic linkage type.
- Nonbonded interactions, exo-anomeric effect, and hydrogen bonding collectively dictate rotameric populations.
- The study provides insights into the conformational flexibility of disaccharides and factors governing their structure.
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