Phosphonomannans

Phosphonomannans (7) are bacterial polymers in which maimo-oligosaccharides are joined by phosphate diester linkages. Phosphonogalactans are present in certain fungi. 

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).]...

Mannans of Hansenula capsulata Y-1842 and H. holstii Y-2448 differ structurally from the phosphonomannan components.83 The man-nan of H. capsulata is probably a cell-wall component, and it has the linear, repeating-structure 6. Other Pichia and Hansenula mannans have predominantly linear structures.84 The 13C-n.m.r. spectrum of 6 (see Fig. 2) is distinguishable from that of the branched-chain man-nan85 from Saccharomyces rouxii (repeating unit 7.)... 

To the phosphonomannan of Hansenula capsulata Y-1842 was attributed the principal structure 15, as, on partial hydrolysis, it gave a mannobiose 6-phosphate (16) which provided 1 mol of formalde-... 

Hansenula holstii NCYC 560 produces cell-wall, and exocellular, phosphorylated mannans of mol. wt. 10°. The cell-wall mannan contains two branched polysaccharides having (l- 2) and (1— 3) linkages, with /3-d, in addition to a-D, linkages. Phosphoric diesters are present. The exocellular phosphonomannan is composed of 3 polymers, each... 

A similar, side-chain structure was found present in the phosphonomannan of S. cerevisiae, except that mannobiose, as well as mannose, was formed on partial acid-hydrolysis, and that the phosphate was linked to 0-6 of 3-unit and 4-unit side-chains.114 Such a structure (20)... 

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. 

All data normalized to D-mannose = 1.0.4F rom Ref. 123 molarity required to produce 50% inhibition of precipitation of lentil lectin with phosphonomannan or glycoprotein. From Ref. 143 minimum amounts (mg/ml) completely inhibiting 4 hemagglutinating doses of lentil lectin, x, no inhibition at 20 mg/ml. "From Ref 213 millimolarity needed to produce 50% inhibition of agglutination. 

Inhibition of the P. sativum Lectin-P. pinus Phosphonomannan Precipitation Reaction by Various Carbohydrates"... 

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... 

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. ... 

The phosphonomannan of Hansenula capsulata has a mannose to phosphate ratio of 2.5 1, which is half that of the H. holstii polymer. It consumed 1.03 moles of sodium periodate with formation of 0.31 mole of formic acid per mole of mannose residue. Autohydrolysis of the phosphonomannan gave 2-0-(6-0-phosphono-a-D-mannopyrano-syl)-D-mannose and a trisaccharide which probably has the structure depicted in (12). The cross reaction of antityphoid horse serum with the phosphonomannan of H. holstii also provides evidence for the presence of (1— 2)- or (1— 3)-linked D-mannopyranose residues, or both. ... 

Wickerham has discussed in detail the relationship of the phos-phonomannans produced by certain Hansenula and Pichia species to their taxonomy and phylogeny. If phosphonomannans should be detected in other fungi, this might indicate a relationship which would aid in the elucidation of the origin of the yeasts. 

Phosphonomannans, fungal, 394,417 Phosphorus, in yeast mannan, 391 Phosphorylases active sites of, 346 amino acids of, 345 kinetics, 289,353 mechanism of action of, 356 properties of, 347... 

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