Characterization of Dynamic Conformations of Oligosaccharides
Oligosaccharides have a significant degree of freedom of movement in solution. Therefore, their interactions with proteins should be described as dynamic processes. NMR spectroscopy can be used to characterize the dynamic conformation of oligosaccharides in solution.
As an expert in the field of nuclear magnetic resonance, Creative Biostructure provides characterization service of dynamic conformations of oligosaccharides for our customers.
Service Content
Our service is the conformational analysis of a series of oligosaccharides. These oligosaccharides carry a set of fate determinants of glycoproteins recognized by intracellular lectins. We use genetically engineered yeast strains to produce isotopically labeled homo oligosaccharides.
The paramagnetic effect, including the pseudo contact displacement induced by lanthanides, provides long-distance geometric information for oligosaccharides and supplements the local conformation information provided by the nuclear Overhauser effect and scalar coupling.
Preparation of Homogeneous Oligosaccharides with Isotope Labeling
Oligosaccharides attached to natural proteins have considerable heterogeneity in covalent structure. In contrast, synthetic technology can produce enough homogeneous oligosaccharides for structural biology research. We have developed various vectors to produce recombinant glycoproteins in mammalian cells, insect cells, silkworms, and plant yeasts.
Figure 1. Schematic of protocols for producing 13C-labeled high-mannose-type oligosaccharides (Kato et al., 2018)
Production of high mannose oligosaccharides using genetically engineered yeast
The combination of metabolic labeling by genetically engineered yeast cells and in vitro reaction catalyzed by glycan processing enzymes is helpful for the systematic preparation of isotopically labeled high mannose oligosaccharides. Stable isotope labeling of oligosaccharides can be achieved by culturing cells in a medium in which glucose is replaced by its isotope-labeled analogues.
| Type of isotope labeling | Labeling methods |
| Uniformly 13C-labeling | The oligosaccharides can be labeled with the use of [13C6] glucose as a metabolic precursor. |
| Position-selective 13C-labeling | Can be performed using an appropriate glucose isotopomer. |
Collection of Conformational Information
The NMR spectral distribution and conformational analysis of oligosaccharides in solution are mainly based on
- Chemical shift
- Scalar coupling
- Nuclear Overhauser effect (NOE)
We combine the uniform and position selective 13C labeling method with the high magnetic field to promote spectral measurement and analysis by improving the sensitivity and resolution and expanding the applicability of isotope editing experiments.
Analysis of Dynamic Conformations of Oligosaccharides
For NMR validation from simulated conformational ensembles, an oligosaccharide ensemble model based on the pseudo-contact shift (PCS) values obtained from MD simulations and experiments is used to determine the anisotropic susceptibility (Δχ) tensor components. In this method, the position of the paramagnetic center is determined by the additional MD calculation of the label part of the coordination La3+. By using the ensemble model with average paramagnetic center Δχ, the tensor of oligosaccharides complexed with paramagnetic ions was estimated Δχ tensor back calculated PCS value to verify the consistency with the experimental data.
Creative Biostructure is committed to providing high-quality NMR analysis services to advance the life sciences fields. If you have any questions or needs, please contact us and our customer service staff will help you the first time.
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Reference
- Kato K, et al. NMR characterization of the dynamic conformations of oligosaccharides. Modern Magnetic Resonance. 2018. 737-754.
