Ribitol teichoic acids

Repeating unit of teichoic acid ribitol phosphate... 

Teichoic acids (16) are bacterial polymers in which alditols, glycerol, or ribitol are joined through the primary hydroxyl groups via phosphate diester linkages. 

FIGURE 9.25 Teichoic acids are covalently linked to the peptidoglycan of Grampositive bacteria. These polymers of (a, b) glycerol phosphate or (c) ribitol phosphate are linked by phosphodiester bonds. 

Ribitol teichoic acid from Bacillus subHUs... 

Several of the intracellular teichoic acids are polymers of glycerol phosphate or ribitol phosphate. An unusual teichoic acid, composed of d-mannitol phosphate, and with pyruvic acid linked as an acetal to 0-4 and 0-5, has been isolated from Brevibacterium iodinum. ... 

Fig. 1.3 A, glycerol teichoic acid B, ribitol teichoic acid G, 3-10 glycosyl Ala, D-alanyl.

Brundish, D.E. and Baddiley, J. (1968) Pneumococcal C-substance, a ribitol teichoic acid containing choline phosphate. BiochemicalJournal 110, 573-582. 

Traces of an optically active anhydroribitol and its phosphates are produced when some teichoic acids are hydrolyzed with alkali.66 67 No anhydroribitol is formed by similar treatment of ribitol, its 1-, 2-, or 3-phosphates, or ribitol 1,5-diphosphate.68 However, small proportions of anhydroribitol and its phosphates are produced by the action of alkali on a synthetic poly (ribitol phosphate) prepared by the action of diphenyl phosphoro-chloridate oil 3,4-O-isopropylideneribitol l-phosphate and 2-phosphate.68 This observation suggests that 1,4-anhydroribitol (13) or its derivatives (15) are produced by fission of a phosphodiester, for example (14), in the manner indicated in Fig. 3, and that this reaction occurs together... 

The proportion of 1,4-anhydroribitol formed by treatment of teichoic acids and synthetic poly(ribitol phosphate) with alkali is small, and the major hydrolytic pathway involves the cyclic phosphate sequence. No 1,4-anhydroribitol glycosides have been observed in the alkaline hydrolyzates of teichoic acids possibly, the presence of a glycosyl substituent makes the reaction sterically less favorable than when such substituents are absent. 

All of the ribitol teichoic acids so far examined are composed of chains of ribitol residues joined through phosphodiester groups at C-l and C-5. Each chain is terminated by a phosphomonoester residue, and the ribitol residues bear glycosyl and D-alanine ester substituents. Detailed structures have been proposed for the polymers from Bacillus aubtilis and Lactobacillus arabinosus, and from two strains of Staphylococcus aureus. The structure of the teichoic acid from Bacillus subtilis was the first to be established in detail the other polymers differ mainly in the nature of the glycosyl substituents. 

A small proportion of O-D-glucosylribitol was produced directly by hydrolysis of the teichoic acid with alkali ( see Fig. 16) this product is identical with that obtained by dephosphorylation of the hydrolysis mixture. The major products of such a hydrolysis with alkali were the isomeric monophosphates (58) and (59), in which R = 0-D-glucopyranosyl, both of which gave the O-D-glucosylribitol on enzymic dephosphorylation. The isomer (58) reduced 3 molar proportions of periodate, and the ribitol residue was oxidized, whereas the isomer (59) reduced 2 molar proportions of periodate, the ribitol residue being resistant to oxidation. Small proportions of the diphosphates (56) and (57) were also produced. Oxidation of the diphosphate (57) with periodate, followed by treatment with alkali to remove the aldehydic residues, gave a ribitol diphosphate. 

The teichoic acid shows an infrared absorption band at 1751 cm.-1, characteristic of carboxylic ester groups, which is not observed in samples from which the D-alanine residues have been removed. Removal of the u-alanine was readily effected with ammonia or hydroxylamine, when D-alaninamide or D-alanine hydroxamate were formed. The kinetics of the reaction with hydroxylamine reveal the high reactivity of its D-alanine ester linkages, which, like those in most other teichoic acids, are activated by the presence of a neighboring phosphate group. That the D-alanine residue is attached directly to the ribitol residues, instead of to the d-glucosyl substituents, was also shown by oxidation with periodate under controlled conditions of pH, when it was found that the D-alanine residues protect the ribitol residues from oxidation. Under the same conditions, all of the ribitol residues were oxidized in a sample of teichoic acid from which the D-alanine had been removed, and it is concluded that the ester groups are attached to C-2 or C-3 of the ribitol residues. 

Approximately equimolar proportions of unsubstituted, monosub-stituted, and disubstituted ribitol residues were present in the teichoic acid examined. However, the proportions differed in other samples, and there is no apparent, regular sequence along the chain. In fact, it is not yet known whether all three types of unit occur in the same polymer molecules, or whether the teichoic acid is a mixture of different molecular species. 

The production of ribitol diphosphates on acid hydrolysis, and also on alkaline hydrolysis, of the product obtained after oxidation of the teichoic acid with periodate establishes the presence of ribitol phosphate residues joined to each other through phosphodiester groups. On oxidation of the polymer (o-alanine removed) with periodate, many of the ribitol residues were oxidized, and the quantitative data obtained support a structure in which there are 7-8 units in the chain. 

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