Polysaccharides assembly

Much of the current knowledge of the biosynthesis of bacterial O-polysaccharide assembly was derived from early studies of the polysaccharides of Salmonella sero-group E [13]. This group consists of a series of four closely related structures belonging to the serogroups Ex - E4 (Table 2). The basic main chain sequence of three monosaccharides, Man-Rha-Gal, seen in the D2 serogroup is the structural element of all four polysaccharides however, in serogroups El5 E2 and E3, E4 the variation oc-... 

Cellulose is the most abundant organic molecule in nature. It is a polysaccharide assembled from glucose monomer units, and it (together with other materials such as hemicellulose and lignin) is the main constituent of plant cell walls. Along with several undigestible polysaccharides, cellulose constitutes the main part of dietary fiber. Specifically cellulose is one of the components of insoluble fiber. 

Starch is the chief storage form of carbohydrate in plants and the most important source of carbohydrate in human nutrition. A starch molecule is a polysaccharide assembled from the simple sugar glucose it can contain anywhere from five hundred to several hundred thousand glucose molecules joined by covalent bonds into a single structure. In addition to its impor-... 

The terpenoids, which are composed of the five-carbon isoprenoids, constitute the largest family of natural products with over 22,000 individual compounds in this class having been described. The terpenoids (hemiterpenes, monoterpenes, sesquiterpenes, diterpenes, triterpenes, tetraterpenes, polyterpenes, and the like) play diverse functional roles in plants as hormones, photosynthetic pigments, electron carriers, mediators of polysaccharide assembly, structural components of membranes, and defense compounds. Many compounds used by man including resins, latex, waxes, and oils contain plant terpenoids. 

Lvov, Y, Onda, M., Ariga, K., and Kunitake, T. 1998. Ultrathin films of charged polysaccharides assembled alternately with linear polyions, /Biomoter Sci Polym Ed 9,345-355. 

This chapter is divided into two sections. The first deals with the general problems and principles of polysaccharide assembly, while the second examines the biosyntheses of various important or interesting polysaccharides, especially where these illustrate general mechanisms. Only a selection of polysaccharides can be considered in detail here, since though so many structures are known or partially known, rather few have been explored in detail from a biosynthetic standpoint. 

Nothing is known of the biosynthesis of most polysaccharide phosphates presumably ATP is the phosphate donor and it is likely that phosphate is added at, or just after, polysaccharide assembly, save where it forms a part of the molecular backbone. 

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