Helical parameters of infinite polymer chains having a diamond-like backbone. application to homopolysaccharides and cyclic oligosaccharides.

Helical conformations of infinite polymer chains may be described by two helical parameters: n and h. General n,h maps have been produced that are independent of the monomer chemistry, except for the limitation of tetrahedral geometry. Some very simple geometrical criteria have been found to underlie the general aspects of the maps obtained. These maps are found to cover the whole range of predictable secondary structures of homopolysaccharides having the (1→2), (1→3), and (1→4) linkage-types. Moreover, a general strategy for investigating the secondary structures of (1→6)-linked homopolysaccharides is proposed. In an extension of these results, the prediction of the possibility of a stable cyclic tetrasaccharide made up of (1→6)-β-D-glucose residues, is proposed and analyzed.