Glucan structural determination

Without doubt, concanavalin A (Con A) is the most celebrated and has proven to be one of the most useful of the plant lectins. Its physical chemical properties and carbohydratebinding properties are well documented in previous reviews [3,8]. Suffice it to note that it was first isolated and crystallized by Sumner and Howell in 1936, who showed it to require metal ions for its activity [74]. By virtue of its interaction with branched a-D-glucans, it is readily prepared by affinity chromatography on crossed-linked dextran (Sephadex) [75, 76]. A homotetramer at pH 7 (subunit M, = 26 500 Da) of Con A has been sequenced [77] and its crystal structure determined both in its native form [38,39] and complexed with methyl a-D-mannopyranoside [40] and Man(al-3)[Man(al-6)]Man[49]. 

Characterization of /J-glucans of different origin Application of nanoprobe NMR for structure determination of arabinoxylan oligosaccharides Assignment of l3C and H NMR spectra of pullulan and isomaltose... 

Biochem. Tokyo) 78, 225. Structural Determination of Glucans from Streptococcus Mutans JC-2(I)ental Caries Bacterium) by Carbon-13 Nuclear Magnetic Resonance. III. 

Xanthan is an extracellular polysaccharide produced by Xanthomonas campestris and related species. The structure of xanthan was determined chemically42,43 as a /3-(l - 4)-linked D-glucan to which are attached trisaccharide side-chains on each second D-glucosyl residue, as depicted in 1Z. 

As the X-ray diffraction diagrams of an oriented gel (Fig. 6) are poorly crystalline, it has been useful to conduct X-ray crystal structure analyses of oligomer of 3-(l->-3)-D-glucan. The molecular structures of laminarabiose and its acetyl derivative have been determined. 

Thus far, the only a-1,4 glucan synthase reported to be overexpressed with high activity is the E. coli enzyme. This system should be further exploited with respect to the methodologies of chemical modification, site-directed mutagenesis, and attempts to determine its three-dimensional structure. 

The main structural constituents of Saccharomyces cerevisiae yeast cell wall are glucans and mannans with a minor proportion of chitin (Walker 1998). Manno-proteins are located in the outer layer of the yeast cell wall and determine most of the surface properties of the wall. Vasserot et al. (1997) studied the capacity of yeast lees to adsorb anthocyanins in an attempt to reduce the detrimental effects of charcoal on the color of red musts and wines. Experiments based on model wine solutions revealed that yeast lees possess a greater affinity for anthocyanins than... 

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