Solid state and solution features of amylose and amylosic fragments

Abstract

An understanding of the molecular changes occurring during polymorphic transformations of amylose is sought through the use of energy calculations. Four stable families of low energy conformers are found; three of these correspond to conformations observed in linear and cyclic maltodextrins in the crystalline state. Upon change of solvent, significant variations have been shown to occur in the relative abundance of amylose conformers. This, in turn, influences properties such as chain extension. The relevance of the stable conformers with respect to helical structures of amylose is analyzed. Whereas one of the conformers would generate a V type shallow helix, another one would give rise to a 6 fold left-handed strand having a 3.6 A advance per residue. This would generate a double helical stranded structure.