Oligosaccharides crystal structure

Table 5. References and selected structural information for the crystal structures of lectin-oligosaccharide crystal structures. ... 

These results suggest that the crystallographic determination of the structure of a productive enzyme-substrate complex is feasible for lysozyme and oligosaccharide substrates. They also provide the information of pH, temperature, and solvent effects on activity which are necessary to choose the best conditions for crystal structure work. The system of choice for human lysozyme is mixed aqueous-organic solvents at -25°C, pH 4.7. Data gathered on the dielectric constant, viscosity, and pH behavior of mixed solvents (Douzou, 1974) enable these conditions to be achieved with precision. 

Diffraction analysis—whether employing x-rays, electrons, or neutrons—is the method of choice for obtaining structural information on crystalline substances. The application of the well understood principles and methods of diffraction analysis to single crystals of sufficient size and perfection can lead to a detailed determination of the crystal structure, without recourse to any auxiliary methodology. Hundreds of mono- and oligosaccharide molecules have been characterized by these means (1), yielding not only an increased understanding of their structures in the solid state, but also a data base useful for extrapolation to other states and molecular interactions. 

Duan, X.Q., Hall, J.A., Nikaido, H., Quiocho, F.A. (2001). Crystal structures of the malto-dextrin/maltose-binding protein complexed with reduced oligosaccharides flexibility of tertiary structure and ligand binding. Journal of Molecular Biology, 306, 1115-1126. 

View of a modified bovine fibrinogen molecule. The 45-nm-long disulfide-linked dimer is composed of three nonidentical polypeptide chains. The N termini of the six chains from the two halves come together in the center in a small globular "disulfide knot." The C termini form globular domains at the ends. The 340-kDa molecule has been treated with a lysine-specific protease which has removed portions of two chains to give the 285-kDa molecule whose crystal structure is shown. Arrows point to attached oligosaccharides. From Brown et at. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 85-90. Courtesy of Carolyn Cohen. 

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. 

W. Saenger Crystal structures of linear and cyclic oligosaccharides A. Eschenmoser Hexose nucleic acids... 

Sawada, M., Tanaka, T., Takai, Y., Hanafusa, T., Taniguchi, T., Kawamura, M., and Uchiyama, T., The crystal structure of cycloinulohexaose produced from inulin by cycloinulo-oligosaccharide fructanotrans-ferase, Carbohydrate Res., 217, 7-17, 1990. 

Watt, D. K., Brasch, D. J., Larsen, D. S., Melton, L. D., and Simpson, J., Oligosaccharides related to xyloglucan-. synthesis and X-ray crystal structure of methyl 2-0-(alpha-L-fucopyranosyl)-beta-D-galactopyranoside. Carbohydr Res 1996,285, 1-15. 

For the carbohydrates especially, the amount of available crystal structural data decreases sharply with molecular complexity [479]. With the exception of the cyclodextrins, discussed in Part III, Chapter 18, there are less than 40 crystal structure analyses of oligosaccharides, of which less than 10 are trisaccharides, one is a tetrasaccharide, and one a hexasaccharide (Part III, Chap. 18). The majority of the basic monosaccharides that are the subunits of the polysaccharides that occur naturally have been studied for example, the pyranose forms of /7-arabinose, a-xylose, a- and -glucose, / fructose, a-sorbose, a-mannose, a- and -galactose, a-fucose, a-rhamnose, N-acetyl glucosamine, and mannosamine (Box 13.2). How-... 

Ramakrishnan B, Balaji PV, Qasba PK. Crystal structure of pi,4-galactosyltransferase complex with UDP-Gal reveals an oligosaccharide acceptor binding site. J. Mol. Biol. 2002 318 491-502. 

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