Teichoic acids types

Five pentoses, namely, D-ribose, d- and L-arabinose, and D- and L-xylose, have been found in hydrolyzates of bacterial polysaccharides. D-Riboseisthe most common of these, and is a component of different LPS, capsular polysaccharides, and teichoic acid type of polymers. In all these polymers, it occurs as the /I-furanosyl group or residue. 

In different polysaccharides of the teichoic acid type, monosaccharides or oligosaccharides are connected by phosphoric diester linkages. Two examples are the capsular antigens from Neisseria meningitides type A (56) and Haemophilus influenzae type c (57), respectively. Glycerol phosphate... 

Gram-positive bacteria also have additional anionic polymers (secondary cell-wall polymers, SCWPs), which are covalently attached to the muramic acid residues of the peptidoglyean and attach cell-surface proteins. They can be of the teichoic acid type, linear copolymers of a sugar alcohol and phosphoric acid, or the teichuronic acid type, in which the anionic component is uronic acids.The commonest teichoic acids are based on 1,3-linked glycerol or 1,5-linked ribitol. 

Cyclic acetals of pyruvic acid are common in extracellular polysaccharides (compare, for example, Ref. 6). They have also been found in some LPS, namely, those from Shigella dysenteriae type 6 and E. coli 0-149 (Ref. 139), and in the teichoic acid from Brevibacterium iodinum. The biosynthesis of these acetals has already been discussed. 

Klebsiella K12, pyruvic acid is acetalically linked to 0-5 and 0-6 of a y -D-galactofuranosyl residue. Pyruvic acid is further acetalically linked to 0-4 and 0-5 of a D-mannitol residue in an unusual type of teichoic acid from Brevibacterium iodinum The absolute configuration at the acetalic carbon atom is (S) in the 5. pneumoniae type 4 polysaccharide, but it has not yet been determined for the other polymers. 

Many bacterial polysaccharides contain phosphoric ester groups. There is a limited number of examples of monoesters. More common are phosphoric diesters, connecting an amino alcohol or an alditol to the polysaccharide chain. Another possibility is that oligosaccharide or oligosaccharide-alditol repeating units are connected to a polymer by phosphoric diester linkages. In addition to the intracellular teichoic acids, several bacteria, for example, different types of Streptococcus pneumoniae, elaborate extracellular polymers of this type. These polymers are generally discussed in connection with the bacterial polysaccharides. 

The major type-specific antigens of Gram-positive bacteria are the teichoic acid moieties associated with the cell wall (see Chapter 1). 

The work of Baddiley and collaborators256 259 on teichoic acids provides excellent examples of the use of deamination in the elucidation of oligosaccharide structure. For example, when treated with nitrous acid (see Scheme 9), the hexasaccharide 140, the repeating unit of the Pneumococcus Type XA capsular polysaccharide, gave 2-... 

Teichoic and teichuronic acids. The cell walls of gram-positive bacteria are composed of a thick peptidoglycan layer which also contains proteins and additional polymers known as teichoic acids and teichuronic acids. In some species these account for 50% of the dry weight of the cells.598 599 Teichoic acids are high polymers of the following general types ... 

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. 

Another physiological role of both types of teichoic acids is their interaction with autolytic enzymes and the regulation of their activity5> 32). 

The teichoic acid in the cell wall of Bacillus subtilis is of the type shown in XIII, and that in Staphylococcus aureus has a structure of the type shown... 

Glyceritol teichoic acid was shown to be present in Lactobacillus casei, Lactobacillus delbruckii, Lactobacillus bulgaricus, Staphylococcus albus, and Staphylococcus citreus, but no ribitol teichoic acid could be detected. The teichoic acid from Staphylococcus albus and Staphylococcus citreus was shown to be present in the walls. The teichoic acid from Lactobacillus casei is of the type shown in formula XV. Walls from Streptococcus faecalis contain both polymers. 

Another type of teichoic acid, which contains a hexopyranosyl phosphate as a part of the main chain, has been characterized by Baddiley and coworkers. The polymer from Staphylococcus lactis 13 has the following structure. 

If phosphogalactomannan does serve a protective function during synthesis of mural proteins, then it may be necessary to add the mannosyl residues to the mannan in a stepwise fashion from GDP-D-mannose rather than in a block from a lipid-linked intermediate mannosyl-containing oligosaccharide. The role of phosphoethanolamine in the proposed protective function may be similar in type to that reported by Holtje and Tomasz for ethan-olamine and choline in cell wall teichoic acid of Diplococcus pneumoniae that is, ethanolamine-containing cell wall teichoic... 

Scanning electron microscopy has revealed concentric circular structures on newly exposed surfaces of the walls and isolated cross-walls of Staphylococcus epidermidis. Extraction of the walls with trichloracetic acid removes most of the phosphorus and about half of the 2-acetamido-2-deoxy-D-glucosyl residues, and destroys this type of structure. Hence, teichoic acid and possibly peptido-glycan (since these polymers are covalently linked) may be arranged circularly on the surface of the wall. 

This relatively simple type of sequence is characteristic of the ribitol teichoic acids and many glycerol teichoic acids, as well as some related phosphorylated polysaccharides. Despite its simplicity the exact nature of the biosynthetic process is rather less well understood than is the case with the complex teichoic acids (above). 

It is possible that some components of the lipoteichoic acid fraction are primers for the synthesis of wall teichoic acid, and are themselves constructed by rather different mechanisms from those above. There is evidence that phosphatidylglycerol in the cell membrane of Staphylococcus aureus can act as a precursor of glycerol in a form of lipoteichoic acid and that this can act as an acceptor for the construction of wall-type teichoic acid (Glaser and Lindsay, 1974). There is also good evidence to suggest that... 

The cell walls and membranes of most Grampositive bacteria contain a series of highly anionic polymers. Quantitatively one of the most important of these is teichoic acid which can be covalently linked to a glycolipid to give a lipoteichoic acid (Fig. 2.10). An alternative type of anionic polymer, which is found in Gram-positive bacteria such as Micrococcus lysodeikticus, is succinylated lipo-mannan (Fig. 2.10). Like teichoic acid, the lipo-mannan is embedded in the membrane by linkage to a diacylglycerol moiety. 

If X = glycerol in Eqnation 10.46a, we have phosphatidyl glycerols (10.51a), and if a further phosphatidyl group is added we get diphosphatidyl glycerols (10.51b). Derivatives of all three types (10.49) have now been isolated from various animal and plant materials. The first of these to be detected was Equation 10.51c in 1942 and this was subseqnently named cardioUpin. Compounds of this kind are closely related to the teichoic acids (below). 

The glycosyl phosphopolyprenols (10.63) are usually classed as a type of glycolipid since they are formed as intermediates in the biosynthesis of teichoic acids and bacterial lipopolysaccharides. 

Certain phosphate esters can be polymerised to give polymers on their own account (homopolymers), with the P atom either in the side chain (12.75) or in the main chain (12.76). Natural polymers of the latter type include the nucleic acids and the teichoic acids (Chapter 10.3). 

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