The structure of V amylose dehydrate: A combined X‐ray and stereochemical approach

Abstract

Abstract Visually integrated, flat‐plate film data were collected from oriented filaments of V amylose dehydrated made from dimethyl sulfoxide–amylose; and X‐ray diffraction and stereochemical methods were used to search a multidimensional parameter space for the most satisfactory description of the crystal and molecular structure. Results indicate that the helical chains are left‐handed and that they pack into the unit cell in an antiparallel arrangement conforming to space group P2 1 2 1 2 1 . Packing is very compact with several O …. O contacts in the range 2.70–2.85 Å between both parallel and antiparallel pairs of chains. Other characteristics of the final model are residue geometry similarity to residue 3 from potassium acetate–cyclohexamylose, O(2) i –O(3) i +1 distance of 2.75 Å, O(6) gg , and O(6) i –O(2) i –6 distance of 2.84 Å. Proton magnetic resonance studies of dried, crystalline V amylose dehydrate powder showed only 0.15 water per glucose residue.