Polysaccharides chemical repeating units

Cartesian and cylindrical polar atomic coordinates of the structural repeating unit of 31 polysaccharide helices are provided in Tables A1 to A31. Errors, if any, in the original publications have been corrected. The coordinates of hydrogen atoms are given in a majority of structures. If missing, they are not available in the references cited in Table I. Each table caption contains the structure number and polymer name assigned in Table I. Refer to Table II for its chemical repeating unit. Cartesian (x, y, z) and cylindrical (r, , z) coordinates are related by x r cost ), y = r sin<(> and z is the same in both systems. 

Pneumococcus, polysaccharides from, 6-7 Poly(a-L-guluronic acid), 353, 355-356,415 Poly(P-D-mannuronic acid), 353-354,414 Polysaccharides, 311 -439 amino sugar derivatives, 166 chemical repeating units, 321, 324-325... 

The primary structure of the extracellular polysaccharide from X. aampestris was recently reinvestigated by Jansson et al. (2), and by Melton et al. (8). The chemical repeat unit is a pentasaccharide. The backbone is a 8-1,4 glucan like cellulose and chitin (9,10) with a trisaccharide side-chain on each cellobiose unit (I). 

V. Lund L. L. Brown J. Li E. Altman, Fish Shellfish Immunol. 2007,23,1095. Elsevier Ltd. Three chemical repeating units, based on the acid-labile feature of Rha residue, were illustrated for each polysaccharide and fragment ions were assigned according to the Domon and Costello nomenclature.49... 

The polysaccharide antigen of Haemophilus influenzae type B has been labelled with tritium by use of a microculture technique using 6-[ H]-D-glucose. Fibre A -ray diffraction patterns have been interpreted for the polysaccharide from Klebsiella K57, and results indicate that the molecule has a three-fold helix with an axially projected repeat unit of 1.143 nm which correlates directly with the chemical repeat unit. ... 

Figure 1. The chemical repeat unit of gellan gum. (The native polysaccharide is partially substituted at C2 with L-glycerate and contains -50% C6 substitution with acetate, both on the (l->3) linked glycosyl residue).

Figure 6. The chemical repeat unit for the bacterial polysaccharides (a) xanthan and (b) acetan.

The polymer 21 contains a reactive olefinic linkage in its repeating unit, and can be modified chemically in various manners. In particular, it is expected that the polymer can be used as a versatile precursor for the chemical synthesis of polysaccharide... 

The trichloroacetimidate method has also found wide applications in the synthesis of various complex oligosaccharides. In the course of the development of chemically defined glycoconjugate vaccines against shigellosis, a decasaccharide, corresponding to two consecutive repeating units of the O-specifk polysaccharide of Shigella... 

The synthesis of the j>. newington O-antigenic polysaccharide by the chemical polymerization pathway will be discussed as an example (J 6 J 7) The first and the most difficult task consists in the preparation of the monomer itself, i. e. , the properly functionalized, oligosaccharide repeating unit. The most usual approach is to introduce the required functions into the already-existing oligosaccharide molecule. 

The chemical polycondensation method has as yet been elaborated only for polymers with 1,2-trans-glycosidic linkages between the repeating units, but within these limits it seems to be a rather broad chemical method. It is the first purely chemical method for the synthesis of complex polysaccharides, as was demonstrated before for polypeptides and polynucleotides. ... 

M. Okada, H. Sumitomo, and K. Ogasawara, Chemical synthesis of polysaccharides. 3. A synthetic polysaccharide having one hydroxyl group in its repeating unit, 3,4-dideoxy-(l- 6)-o -DL-t/zreo-hexopyranan, Polym. J. (Tokyo), 15 (1983) 821-826. 

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