Mannans structure

The structures of the cell-wall D-mannans of several other yeasts have been investigated381 by use of this exo-a-D-mannanase. Five were degraded to the (l->6)-a-D-mannan chain. Those which contained jB-linked d-mannosyl units or a-D-galactosyl groups in the side chains were not significantly hydrolyzed. However, removal, by partial hydrolysis with acid, of the a-D-galactosyl units from five galactomannans, and of /3-linked D-mannosyl units from three other D-mannans, rendered these polysaccharides partially susceptible to hydrolysis by exo-a-D-mannanase, consistent with an a-linked-D-mannan structure. 

Work on glucan and mannan structures is described in Refs. 105-108a. Taylor and Cameron109 have reviewed the preparation and quantitative analysis of fungal cell-walls. 

Five, genetically distinct, /8-D-fructofuranosidases have been described for strains of Saccharomyces hybrids. The behavior and kinetics of each enzyme are very similar.362,451 W. L. Smith and Ballou have purified the mannan-protein /3-D-fructofiiranosidases of three strains of Saccharomyces cerevisiae whose cell walls have differences in mannan structure.452 By use of immunochemical methods, they found that the structure of each /3-D-fructofuranosidase mannan is similar to that of the cell wall of the corresponding strain only. Mutations affecting the structure of the one also produced similar changes in the other. 

In this section, I consider the variants in Saccharomyces mannan structure that occur naturally and those that have been produced by directed mutation. From a comparison of their aceto-lysis patterns, three interfertile wild-type Saccharomyces species have been distinguished. These differ only in the lengths of their longest side chains that, in turn, reflect the activities of two presumably different al 3-inannosyltransferases (Figure 6). Diploids of strains A and B have the B phenotype, whereas diploids of either A or B with C have the C phenotype, which suggests that... 

Rather interestingly, protease-defident mutants of P. n vabs bind eater amounts of both C3b and C5b-9 and are ph ocytosed more readily, yet remain serum resistant. Recent data have shown that complement resistance in P.pnffvalis does not depend on protease production but requires expression of cell surface polysaccharide, which is an anionic branched mannan structure. Similarly, loss of Y.pestis Pla expression docs not affect resistance to human complement, although Pla-negative mutants show decreased virulence murine infection models. - " Complement deaving proteases may serve to limit anaphylatoxin generation and neutrophil influx rather than serving as the primary mechanism of serum resistance. 

L.R.S. Moreira, and E.X.F. Filho, An overview of mannan structure and mannan-degrading... 

Scheme 8.9). The C NMR and optical rotation of trisaccharide 26 were identical to those reported by Lichtenthaler (vide supra) [36]. Crich and co-workers have also successfully applied their methodology towards the synthesis of complex P-mannan structures [48] and the mannosyl erythritol lipid MEL A [49]. 

Antalis, C., Fogel, S. and Ballou, C. E, (1973) Genetic control of yeast mannan structure. Mapping the first gene concerned with mannan biosynthesis. J. Biol. Chem. 248, 4655-4659. 

Hirayama, S., Furukawa, S., Ogihara, H., and Morinaga, Y. (2012) Yeast mannan structure necessary for co-aggregation with Lactobacillusplantarum MLll-11. Biochem Biophys Res Commun 419, 652-655. 

Benzyl derivatives of (1 6)-a-D-glucan, (l->6)-a-D-mannan, and (l-> 6)-a-D-galactan have been studied in 1,4-dioxane. These derivatives have complex and interesting c.d. spectra due to the ww transition of the chromophore with resolved vibrational structure. However, a conformational interpretation of these interesting spectra is not possible at this time. 

Saraf, S.R., Rogers, W.J., Mannan, M.S. (2003) Prediction ofReactive Hazards Based on Molecular Structure. Journal of Hazardous Material, A98, 15-29. 

In this context, Lindhorst et al. proposed biological investigations of pentaerythri-tol-based mannoside clusters to test their capacity to block the binding of E. coli to yeast mannan in vitro.75 In all of the proposed structures, and according to a rational approach, pentaerythritol itself, as well as the included C3 spacers, were used as structural components for substituting the inner regions of the monosaccharide moieties (Scheme 4). The tetravalent cluster 27 has been efficiently synthesized according... 

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