Klebsiella three-fold helical conformation

Figure 10. Computer-generated projections of a left-handed three-fold helical conformation for Klebsiella K16...

The final Klebsiella polysaccharide that will be mentioned specifically is KZS, whose chemical structure was determined by Niemann et al (24) (Figure 30). This polysaccharide is of particular interesT because its backbone consists of a similar alternating 1, 3 diequatorial, 1, 4 diequatorial glycosidic linkage geometry to that found in the connective tissue polysaccharides, hyaluronic acid, chondroitin sulphate and dermatan sulphate (25). All these three polysaccharides have exhibited 3-fold helical conformations with axially projected chemical repeats in the range 0.95 - 0.97 nm which is comparable to 0.97 nm found in K25 which also forms a 3-fold helix (14). Further, left-handed helices were found to be more favourable in K25 as has previously been observed in the connective tissue polysaccharides. The similarities between these various different structures is apparent in Figure 31 which shows projections down the axis of K25 and several of the connective tissue polysaccharides. 

Figure 31. Computer-generated projections down the helix axis of the three-fold left-handed helical conformations of Klebsiella K25, Hyaluronic acid, HA, Chon-droitin 4-sulphate, C4-S, and Chondroitin 6-sulphate, C6-S...

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