O-Phosphonomannan

O-Phosphonomannans containing phosphoric diester bridges lend themselves to a similar approach, as 13C-C-0-31P couplings may be interpreted in the same way. This subject is discussed in Section VI,8. 

Such studies, and others on an O-phosphonomannan155 and a tei-choic acid,168 relied on judicious comparisons (of shift) with signals of model compounds, and these are simpler than conventional, analytical procedures. For example, it is difficult to methylate alkali-labile O-phosphonomannans, and sialic acid and KDO-containing polymers would require difficultly available, O-methylated standards. In addition, periodate-oxidation analyses are restricted to polymers having fortuitously amenable, chemical structures. 

In addition to the coupled-signal method just described, phosphorylated carbon signals can be detected by use of praseodymium chloride, which displaces a- and /8-carbon resonances of a,/8-D-mannose 6-phosphate and a-D-mannosyl phosphate downfield, with little effect on other resonances. Europium chloride has analogous properties, except that the displacements are upfield. With certain polysaccharides, such as the O-phosphonomannan of Hansenula capsulata (29), the sig-... 

Initially, the O-phosphonomannan was assigned a repeating unit of 2-0-/8-D-mannopyranosyl-a-D-mannopyranose joined by (1— -phosphoric diester bridges (30). With a- and /8-D-mannopyranosyl units, it... 

Fig. 33.—13C-N.m.r. Spectra of O-Phosphonomannan (29) in D20 at 33° (A) and the Selective Signal-Displacements Occurring on Addition of PrCl3-6 H20 (B) and EuC13-6 H20 (C). [Tins spectra were recorded using an external standard of tetramethyl-silane (8C = 0).]...

By utilizing the Ouchterlony technique of two-dimensional, agar-gel diffusion, Slodki and his colleagues investigated the interaction of con A with O-phosphonomannans.363 They suggested a possible correlation between the extent of precipitate formation with con A and the content of a-D-(l— 2)-mannosidic linkages. 

The O-phosphonomannan from Pichia pinus effectively inhibited hemagglutination and also precipitated with the lectin both in agar-gel double-diffusion and in solution.123 The flocculation profile was very similar to an antibody-antigen precipitin curve, and proceeded best at 20°, pH 6-8, and an ionic strength >0.1. 

The pea lectin precipitated with muscle glycogen, yeast mannan from Saccharomyces cerevisiae, and O-phosphonomannan from Pichia pinus.122 All of these reactions were inhibited by specific, sugar haptens (D-mannose, D-glucose, and D-fructose).122... 

O-Phosphonomannan/mannan Hansenula sp. Hansenula capsulata Hansenula holstii Pichia sp. Selenotila peltata... 

Figure 3. Repeat units of poly (phosphoric diester) O-phosphonomannans the unit depicted for Hansenula capsulata is a trimer...

Autohydrolysis of periodate-oxidized phosphonomannan gave 3-O-a-D-mannopyranosyl-D-mannose and O-a-D-mannopyranosyl-(l- 3)-0-Q -D-niannopyranosyl-(l- 3)-D-mannose. ... 

O-Phosphono-D-mannans have been isolated from several strains of yeast. Stewart and Ballou have observed a great variation in the phosphorus content of diflFerent mannans, the highest being in Kloeckera brevis mannan, which has one phosphorus atom for every nine D-mannose residues. These phosphonomannans appeared to have a structure similar to that of the mannan already described, except for the presence of phosphate groups. ... 

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